Answer:
The probability that the sixth customer buys sour milk is [tex]\frac{1}{5}[/tex].
Step-by-step explanation:
The grocery store has a total of 10 cartons of milk.
The number of cartons of milk that are sour is, 2.
If none of the sour cartons of milk were bought by the first 5 buyers, then the probability of this event is:P (Both the sour cartons are available to be sold to the sixth customer)
= [tex]P(2\ sour\ cartons)=\frac{2}{5}[/tex]
If only one sour carton of milk is sold to the first 5 buyers then the probability is:P (Only one sour cartons is available to be sold to the sixth customer)
= [tex]P(1\ sour\ cartons)=\frac{1}{5}[/tex]
If both the sour carton of milk is sold to the first 5 buyers then the probability is:P (None of the sour cartons is available to be sold to the sixth customer)
= [tex]P(0\ sour\ cartons)=\frac{0}{5}[/tex]
Compute the probability that the sixth customer buys sour milk:
= P (Both sour milk is available for the 6th customer) +
P (Only one sour milk is available for the 6th customer) +
P (None of the sour milk is available for the 6th customer)
[tex]=\frac{{8\choose 5}{2\choose 0}}{{10\choose 5}} \times\frac{2}{5} +\frac{{8\choose 4}{2\choose 1}}{{10\choose 5}} \times\frac{1}{5} +\frac{{8\choose 3}{2\choose 2}}{{10\choose 5}} \times\frac{0}{5} \\=\frac{56\times2}{252\times5} +\frac{140\times1}{252\times5} +0\\=\frac{1}{5}[/tex]
Thus, the probability that the sixth customer buys sour milk is [tex]\frac{1}{5}[/tex].
A small island is 3 miles from the nearest point P on the straight shoreline of a large lake. If a woman on the island can row a boat 3 miles per hour and can walk 4 miles per hour, where should the boat be landed in order to arrive at a town 12 miles down the shore from P in the least time? Let x be the distance between point P and where the boat lands on the lakeshore. Hint: time is distance divided by speed.
Answer:
The trip consists of two parts. The rowing part is the hypotenuse of right angled triangle
whose sides are the distance from P to the island, which is 5, and the distance between P and
the landing point of the rowboat on the shore, which is x
so this part of trip is sqrt(25+ x^2)
The 2nd part is the walking part, which is (8-x)
Distance = rate times time (D = rt), so to get the time you have t = D/r. We must divide each
of the trip by the appropriate rate to get the time.
a) T(x) = sqrt(25+x^2)/3 + (8-x)/4
To find minimum time required take derivative of the T(x) function and find it's zeros
T'(x) = x/(3(sqrt(25+x^2)) - 1/4 = 0
x/(3(sqrt(25+x^2)) = 1/4
4x = 3sqrt(25+x^2
16x^2 = 9(25+x^2) = 225 + 9x^2
7x^2 = 225
x^2 = 225/7
x = sqrt(225/7) = 5.669467 miles
T(x) = 3.602386382 hours
Step-by-step explanation:
The point where the boat should be landed can be found by expressing
the distance travelled on the boat and walking as a function of time.
The point where the boat should be landed is the point 3.4 miles from the
point P towards the town.
Reasons:
x represent the distance from point P to the boat landing point.
Therefore, distance of rowing the boat = √((12 - x)² + 3²)
The total time, t, is therefore;
[tex]t = \dfrac{12-x}{4} +\dfrac{\sqrt{x^2 + 3^2} }{3}[/tex]
When the time is minimum, we get;
[tex]\dfrac{dt}{dx} = \dfrac{d}{dx} \left( \dfrac{12-x}{4} +\dfrac{\sqrt{x^2 + 3^2} }{3} \right) = \dfrac{12\cdot \left(-3 + 4 \cdot\dfrac{2 \cdot x }{2\cdot \sqrt{x^2 + 9} } \right)}{144}[/tex]
[tex]\dfrac{12\cdot \left(-3 + 4 \cdot\dfrac{2 \cdot x }{2\cdot \sqrt{x^2 + 9} } \right)}{144} = -\dfrac{1}{4} +\dfrac{x }{3 \cdot \sqrt{x^2 +9} }[/tex]
[tex]\dfrac{x }{3 \cdot \sqrt{x^2 +9} } = \dfrac{1}{4}[/tex]
4·x = 3·√(x² + 9)
16·x² = 9·(x² + 9)
7·x² = 81
[tex]x = \dfrac{9 \cdot \sqrt{7} }{7}[/tex]
x ≈ 3.4 miles.
The point where the boat should be landed is the point approximately 3.4
miles from the point P in the direction of the town.
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The sum of 5 times a number and
minus −2, plus 7 times a number
Answer:
12x + 2
Step-by-step explanation:
Let the number be represented by x.
Then five times the number = 5*x
Seven times the number = 7*x
Sum of 5 times the number minus -2 = [tex]\[5*x - (-2)\][/tex] = [tex]\[5x +2\][/tex]
Adding seven times the number to this expression yields, [tex]\[5x+2+7x\][/tex]
[tex]\[= (5+7)x+2\][/tex]
[tex]\[= 12x+2\][/tex]
So the simplified expression corresponds to 12x + 2.
A sample of 100 cars driving on a freeway during a morning commute was drawn, and the number of occupants in each car was recorded. The results were as follows: NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part.
Occupants 1 2 3 4 5
Number of Cars 71 16 8 3 2
a. For what proportion of cars was the number of occupants more than one standard deviation greater than the mean? (Round the final answer to two decimal places.)
Answer: 29%
Step-by-step explanation:
I considered the question to be: for what proportion of cars was the number of occupants more than 1 standard deviation and greater than the mean.
The first step is to calculate the weighted mean of the number of occupants in the cars. The next step is to determine the standard deviation using the formula √[ Σ ( xi - μ )² / N ]. Subsequently, identify the number of occupants that are more than one standard deviation greater than the mean.
Explanation:In this question, we're asked to calculate the proportion of cars that had more than one standard deviation above the mean number of occupants. First, we need to calculate the weighted mean (average) of the number of occupants in the cars. Based on the data, the mean can be calculated as:
Mean = (1*71 + 2*16 + 3*8 + 4*3 + 5*2) / 100 = 1.66
Next, we find the standard deviation. The standard deviation tells us how spread out the numbers are from the mean. Calculating standard deviation is a bit involved. The formula is √[ Σ ( xi - μ )² / N ]. Once you have these, look at the number of occupants that are more than one standard deviation greater than this mean.
Note: This is a statistical analysis question that requires knowledge of the concepts of mean and standard deviation.
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Find tea. Write your answer in simplest radical form
Answer:
2√6 ft
Step-by-step explanation:
Tan Ф = opposite/ adjacent
tan 60 = t / 2√2 ft
tan 60 = √3
t = (tan 60 )(2√2 ft)
t = (√3)(2√2 ft) = 2√6 ft
Suppose you received a score of 95 out of 100 on exam 1 . The mean was 79 and the standard deviation was 8 . If your score on exam 2 is 90 out of 100 , and the mean was 60 with a standard deviation of 15 , then you did:
better on exam 1 .
worse on exam 1 .
the same on both exams.
worse on exam 2
Answer:
You did the same on both exams.
Step-by-step explanation:
To compare both the scores, we need to compute the z scores of both the exams and then compare the values. The formula for z-score is:
Z = (X - μ)/σ
Where X = score obtained
μ = mean score
σ = standard deviation
For Exam 1:
Z = (95 - 79)/8
= 16/8
Z = 2
For Exam 2:
Z = (90 - 60)/15
= 30/15
Z = 2
The z-scores for both the tests are same hence the third option is correct i.e. you did the same on both exams.
Your performance on exam 1 and exam 2 can be compared using Z-scores, which measure how many standard deviations a score is from the mean. You scored 2 standard deviations above the mean on both exams, so you did the same on both exams.
Explanation:In this question, your performance on exams is being compared relative to the mean of the class scores and their standard deviation. This is a concept in statistics known as Z-scores. The Z-score tells us how many standard deviations an observation (your score) is from the mean. The formula for Z-score is (observation - mean) / standard deviation.
For exam 1 your Z - score is (95-79) / 8 which equals 2. This means you scored 2 standard deviations above the mean on exam 1. For exam 2, your Z-score is (90-60) / 15 which equals 2. Again, this means you scored 2 standard deviations above the mean on exam 2. Because your Z-score for both exams is the same, you did the same on both exams.
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Courtney is picking out material for her new quilt. At the fabric store, there are 9 solids, 7 striped prints, and 5 floral prints that she can choose from. If she needs 2 solids, 4 floral prints, and 4 striped fabrics for her quilt, how many different ways can she choose the materials?
Answer:
N = 6300 ways
She can choose the materials 6300 ways
Step-by-step explanation:
In this case order of selection is not important, so we use combination.
For solids,
She needs 2 out of 9 available solids = 9C2
For striped prints
She needs 4 out of 7 available = 7C4
For floral prints
She needs 4 out of 5 available = 5C4
The total number of ways she can choose the materials is;
N = 9C2 × 7C4 × 5C4
N = 9/(7!2!) × 7/(4!3!) × 5/(4!1!)
N = 6300 ways
To find the number of different ways Courtney can choose the materials for her quilt, we can use the concept of combinations. The total number of ways she can choose the materials is the product of the number of choices for each type of fabric.
Explanation:To find the number of different ways Courtney can choose the materials for her quilt, we can use the concept of combinations. The total number of ways she can choose the materials is given by the product of the number of choices for each type of fabric. So, the answer is:
Total number of ways = number of ways to choose solids * number of ways to choose floral prints * number of ways to choose striped fabrics
Given that she needs 2 solids, 4 floral prints, and 4 striped fabrics, we can calculate:
Number of ways to choose solids = combinations(9, 2) = 36Number of ways to choose floral prints = combinations(5, 4) = 5Number of ways to choose striped fabrics = combinations(7, 4) = 35Substituting these values into the formula:
Total number of ways = 36 * 5 * 35 = 6300
So, there are 6300 different ways Courtney can choose the materials for her quilt.
There are two traffic lights on Darlene's route from home to work. Let E denote the event that Darlene must stop at the first light, and define the event F in a similar manner for the second light. Suppose that P(E) = 0.2, P(F) = 0.3, and P(E ∩ F) = 0.13.
Answer:
The question is incomplete, below is the complete question,"There are two traffic lights on Darlene's route from home to work. Let E denote the event that Darlene must stop at the first light, and define the event F in a similar manner for the second light. Suppose that P(E) = 0.2, P(F) = 0.3, and P(E ∩ F) = 0.13.
a) What is the probability that the individual needn't stop at either light?
b) What is the probability that the individual must stop at exactly one of the two lights? c) What is the probability that the individual must stop just at the first light?"
Answer:
A. 0.63
B. 0.24
C. 0.07
Step-by-step explanation:
Data given,
P(E) = 0.2, P(F) = 0.3, and P(E ∩ F) = 0.13.
From the question, we can conclude that the event are dependent, hence
a. P(needn't stop at either light) = 1 - P(Need to stop at either light)
P(EUF)' =1-P(EUF)
P(EUF)' =1- (P(E)+P(F) -P(E ∩ F))
P(EUF)' =1-(0.2+0.3-0.13)
P(EUF)' =1-0.37
P(EUF)' =0.63
b. P(must stop at exactly one of the two lights) = P(must stop at either light) - P(must stop at both lights)
P(must stop at exactly one of the two lights) = P(E u F) - P(En F)
but P(E u F)=0.37,
P(En F)=0.13,
P(must stop at exactly one of the two lights) = 0.37 - 0.13 = 0.24
c. P(must stop at just the first light) = P(must stop at either light) - P(must stop at the second light)
P(must stop at just the first light) = P(E u F)-P(F)
P(must stop at just the first light) = 0.37 - 0.3 = 0.07
The question deals with the topic of Probability in Mathematics. It presents the probabilities of two events, denoted as E and F, which are stopping at the first and second traffic lights, respectively. The question also provides the concurrent occurrence of both events.
Explanation:The mathematics topic this question deals with is Probability. In the scenario given, E represents the event that Darlene must stop at the first traffic light and F represents the event that she needs to stop at the second traffic light. The probabilities of these events are given as P(E)=0.2 and P(F)=0.3, respectively. Additionally, we're given that the probability of both events happening (denoted P(E ∩ F)) is 0.13.
In order to analyze the situation, we can leverage the rule of joint probability, which states that the probability of two independent events both happening is the product of their individual probabilities. However, in this case the events E and F are not independent (since the probability of the intersection P(E ∩ F) is not equal to the product of probabilities P(E)*P(F)) so we know that the occurrence of E does influence the occurrence of F, and vice versa.
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The top three corn producers in the world-country A, country B, and country C-grew a total of about 676 million metric tons (MT) of con in 2014 The country A produced 60 million MT more than the combined production of country B and country C Country B produced 122 million MT more than country C. Find the number of metric tons of com produced by each country The country Aproduced□minon MT ofcorn, the country B produced The country A producedmilsion MT of corn, the country B produced mition MT of corn, and the country C produced million MT of corn mati on MT of corn, and the country Cproduced□ma on MT of corn
Answer:
x = 368 production of country A (millions of (MT)
y = 215 production of country B (millions of (MT)
z = 93 production of country C (millions of (MT)
Step-by-step explanation:
Let call production as follows
Country A production x millions on MT
Country B production y millions on MT
Country C production z millions on MT
Then according to problem statement
x + y + z = 676 (1)
x = 60 + y + z
y = 122 + z
That system ( 3 equations and three unknown varables ) could be solved by any of the available procedures.
By subtitution we get
x = 60 + 122 + z + z ⇒ x = 182 + 2*z
And
182 + 2*z + 122 + z + z = 676
Solving for z
304 + 4*z = 676 ⇒ 4*z = 676 - 304 ⇒ 4*z = 372
z = 372/4 ⇒ z = 93 millions of (MT)
And
y = 122 + z ⇒ y = 122 + 93 ⇒ y = 215 millions of (MT)
x = 182 + 2*z ⇒ x = 182 + 2 ( 93) ⇒ x = 182 + 186
x = 368 millions of (MT)
We can cheked in equation 1
x = 368
y = 215
z = 93
Give a total of 676 millions of (MT)
For these types of questions, first click the line tool on the tool palette labelled PFloor, and plot by clicking your mouse for the first end-point -- touching the vertical axis then moving your mouse to the right and clicking again for the second end-point. The new line should intersect both the D1 and S1 lines and have a height greater than 50 as measured on the vertical axis.
To Plotting lines , use the PFloor line tool and click your mouse for the first and second end-points, ensuring that the line intersects both the D1 and S1 lines and has a height greater than 50.
To plot the line described in the question, follow these steps:
Select the line tool on the tool palette labeled PFloor.
Click your mouse for the first end-point on the vertical axis.
Move your mouse to the right and click again for the second end-point.
The new line should intersect both the D1 and S1 lines and have a height greater than 50 on the vertical axis.
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Try to sketch by hand the curve of intersection of the parabolic cylinder y = x2 and the top half of the ellipsoid x2 + 7y2 + 7z2 = 49. Then find parametric equations for this curve.
To sketch the curve of intersection, we substitute the equation of the parabolic cylinder into the equation of the ellipsoid. We use the discriminant to determine the nature of the curve and find its parametric equations.
Explanation:To sketch the curve of intersection of the parabolic cylinder and the top half of the ellipsoid, we can substitute the equation of the parabolic cylinder into the equation of the ellipsoid and then solve for the remaining variable. By doing this, we obtain a quadratic equation.
We can then use the discriminant to determine the nature of the solutions, which will help us identify if the curve is a parabola or an ellipse. Based on the discriminant, we can find the parametric equations for the curve and determine its shape.
For example, if the quadratic equation has two distinct real solutions, then the curve is an ellipse, but if it has one repeated real solution, the curve is a parabola.
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A sample of 16 people is taken and their weights are measured. The standard deviation of these 16 measurements is computed to be 5.8. What is the variance of these measurements?
Answer:
The variance of given sample is 33.64 square pounds.
Step-by-step explanation:
We are given the following in the question:
Sample size, n = 16
Standard deviation, s = 5.8 pounds
We have to find the variance of the given sample.
Variance is the square of the standard deviation.
[tex]\text{Variance} = (\text{Standard Deviation})^2\\= (5.8\text{ pounds})^2\\=33.64\text{ pound}^2[/tex]
Thus, the variance of given sample is 33.64 square pounds.
Lillian earns $44 in 4 hours. At this rate, how many dollars will she earn
in 30 hours?
1 of 38 QUESTIONS
$440
$300
O $330
$110
SUBMIT
Answer:
(44/4)*30 = $330
Step-by-step explanation:
divide by four and multiply by 30
The computers of nine engineers at a certain company are to be replaced. Four of the engineers have selected laptops and the other 5 have selected desktops. Suppose that four computers are randomly selected.
(a) How many different ways are there to select four of the eight computers to be set up?
(b) What is the probability that exactly three of the selected computers are desktops?
(c) What is the probability that at least three desktops are selected?
Answer:
(a) There are 70 different ways set up 4 computers out of 8.
(b) The probability that exactly three of the selected computers are desktops is 0.305.
(c) The probability that at least three of the selected computers are desktops is 0.401.
Step-by-step explanation:
Of the 9 new computers 4 are laptops and 5 are desktop.
Let X = a laptop is selected and Y = a desktop is selected.
The probability of selecting a laptop is = [tex]P(Laptop) = p_{X} = \frac{4}{9}[/tex]
The probability of selecting a desktop is = [tex]P(Desktop) = p_{Y} = \frac{5}{9}[/tex]
Then both X and Y follows Binomial distribution.
[tex]X\sim Bin(9, \frac{4}{9})\\ Y\sim Bin(9, \frac{5}{9})[/tex]
The probability function of a binomial distribution is:
[tex]P(U=k)={n\choose k}\times(p)^{k}\times (1-p)^{n-k}[/tex]
(a)
Combination is used to determine the number of ways to select k objects from n distinct objects without replacement.
It is denotes as: [tex]{n\choose k}=\frac{n!}{k!(n-k)!}[/tex]
In this case 4 computers are to selected of 8 to be set up. Since there cannot be replacement, i.e. we cannot set up one computer twice or thrice, use combinations to determine the number of ways to set up 4 computers of 8.
The number of ways to set up 4 computers of 8 is:
[tex]{8\choose 4}=\frac{8!}{4!(8-4)!}\\=\frac{8!}{4!\times 4!} \\=70[/tex]
Thus, there are 70 different ways set up 4 computers out of 8.
(b)
It is provided that 4 computers are randomly selected.
Compute the probability that exactly 3 of the 4 computers selected are desktops as follows:
[tex]P(Y=3)={4\choose 3}\times(\frac{5}{9})^{3}\times (1-\frac{5}{9})^{4-3}\\=4\times\frac{125}{729}\times\frac{4}{9}\\ =0.304832\\\approx0.305[/tex]
Thus, the probability that exactly three of the selected computers are desktops is 0.305.
(c)
Compute the probability that of the 4 computers selected at least 3 are desktops as follows:
[tex]P(Y\geq 3)=1-P(Y<3)\\=1-[P(Y=0)+P(Y=1)+P(Y=2)]\\=1-[({4\choose 0}\times(\frac{5}{9} )^{0}\times (1-\frac{5}{9} )^{4-0}+({4\choose 1}\times(\frac{5}{9} )^{1}\times (1-\frac{5}{9} )^{4-1}+({4\choose 2}\times(\frac{5}{9} )^{2}\times (1-\frac{5}{9} )^{4-2}]\\=1-0.59918\\=0.40082\\\approx0.401[/tex]
Thus, the probability that at least three of the selected computers are desktops is 0.401.
Data for an economy show that the unemployment rate is 6 percent, the participation rate is 60 percent, and 200 million people 16 years or older are not in the labor force. How many people are in the labor force in this economy
Answer:
300 million people
Step-by-step explanation:
If the participation rate is 60% and 200 million people 16 years or older are not in the labor force, it means that 200 million corresponds to 40% of people 16 years or older. Since 60% of people 16 years or older are in the labor force, the total number of people in the labor force is given by:
[tex]n=\frac{200}{0.4}-200\\ n= 300\ million\ people[/tex]
300 million people are in the labor force in this economy.
The histogram displays the number of 2012 births among U.S. women ages 10 to 50 . Each bin represents an interval of two years, and the height of each bin represents the frequency with which the data fall within that interval?
Answer:
Number of births to women below 22 years of age: 830
% of births occurred to women of age between 34 and 36: 6.35%
Step-by-step explanation:
There are two parts to this question:
To calculate the number of births, we look at the histogram below.
We see that each bar has a number on top, suggesting that particular for the age limit. Number of births to women below age of 22, we start adding all numbers below the mark of 22 on x-axis:
⇒ 39+134+29+363 = 830
To calculate the percentage, we divide the number of births in that particular interval by total number of births and then multiply by 100.
To calculate the total number of births, we add all the numbers on the top of the bars:
⇒ 39+ 134+294+363+391+425+460+474+432+343+250+163+98+49+17+4+1 Total births = 3937
[tex]\frac{250}{3937} \times 100\\ 0.0635 \times 100\\= 6.35 \%[/tex]
According to the 2010 Census, 11.4% of all housing units in the United States were vacant. A county supervisor wonders if her county is different from this proportion. She randomly selects 850 housing units in her county and finds that 129 of the housing units are vacant. Write the null hypothesis and the alternative hypothesis Do a Test of Hypothesis and write the P-value. Write your conclusion: Construct a 95% cl for the true proportion of vacant houses in the supervisor's county. Does the confidence interval support your conclusion. Explain briefly.
Answer:
Null hypothesis:[tex]p=0.114[/tex]
Alternative hypothesis:[tex]p \neq 0.114[/tex]
[tex]z=\frac{0.152 -0.114}{\sqrt{\frac{0.114(1-0.114)}{850}}}=3.49[/tex]
Since is a bilateral test the p value would be:
[tex]p_v =2*P(z>3.49)=0.00049[/tex]
So the p value obtained was a very low value and using the significance level given [tex]\alpha=0.05[/tex] we have [tex]p_v<\alpha[/tex] so we can conclude that we have enough evidence to reject the null hypothesis.
[tex]0.152 - 1.96 \sqrt{\frac{0.152(1-0.152)}{850}}=0.128[/tex]
[tex]0.152 - 1.96 \sqrt{\frac{0.152(1-0.152)}{850}}=0.176[/tex]
And the 95% confidence interval would be given (0.128;0.176).
And support the conclusion obtained on the hypothesis test since the value of 0.114 is not in the confidence interval, so we have enough evidence to reject the null hypothesis.
Step-by-step explanation:
Data given and notation
n=850 represent the random sample taken
X=129 represent the number of housing units that are vacant.
[tex]\hat p=\frac{129}{850}=0.152[/tex] estimated proportion of housing units that are vacant.
[tex]p_o=0.114[/tex] is the value that we want to test
[tex]\alpha=0.05[/tex] represent the significance level
Confidence=95% or 0.95
z would represent the statistic (variable of interest)
[tex]p_v[/tex] represent the p value (variable of interest)
Concepts and formulas to use
We need to conduct a hypothesis in order to test the claim that the proportion is equal is 0.114 or not:
Null hypothesis:[tex]p=0.114[/tex]
Alternative hypothesis:[tex]p \neq 0.114[/tex]
When we conduct a proportion test we need to use the z statistic, and the is given by:
[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)
The One-Sample Proportion Test is used to assess whether a population proportion [tex]\hat p[/tex] is significantly different from a hypothesized value [tex]p_o[/tex].
Calculate the statistic
Since we have all the info requires we can replace in formula (1) like this:
[tex]z=\frac{0.152 -0.114}{\sqrt{\frac{0.114(1-0.114)}{850}}}=3.49[/tex]
Statistical decision
It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.
The significance level assumed is [tex]\alpha=0.05[/tex]. The next step would be calculate the p value for this test.
Since is a bilateral test the p value would be:
[tex]p_v =2*P(z>3.49)=0.00049[/tex]
So the p value obtained was a very low value and using the significance level given [tex]\alpha=0.05[/tex] we have [tex]p_v<\alpha[/tex] so we can conclude that we have enough evidence to reject the null hypothesis.
Confidence interval
The confidence interval would be given by this formula
[tex]\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]
For the 95% confidence interval the value of [tex]\alpha=1-0.95=0.05[/tex] and [tex]\alpha/2=0.025[/tex], with that value we can find the quantile required for the interval in the normal standard distribution.
[tex]z_{\alpha/2}=1.96[/tex]
And replacing into the confidence interval formula we got:
[tex]0.152 - 1.96 \sqrt{\frac{0.152(1-0.152)}{850}}=0.128[/tex]
[tex]0.152 - 1.96 \sqrt{\frac{0.152(1-0.152)}{850}}=0.176[/tex]
And the 95% confidence interval would be given (0.128;0.176).
And support the conclusion obtained on the hypothesis test since the value of 0.114 is not in the confidence interval, so we have enough evidence to reject the null hypothesis.
We first set the null and alternative hypothesis and then conduct a z-test for proportions to calculate the z-score and subsequently the p-value. We use the p-value to decide whether to reject the null hypothesis. Finally, we construct a 95% confidence interval for the true proportion of vacant houses and check if this supports our test conclusion.
Explanation:Firstly, define the proportion of vacant housing units in the country as p0 and in the randomly selected county as p. The null hypothesis (H0) states that the county isn't different, so H0: p = p0 = 0.114. The alternative hypothesis (Ha) would be that the county is different, so Ha: p ≠ 0.114.
Let's conduct a Test of Hypothesis using a z-test for proportions. The z-score is calculated as (p - p0) / sqrt((p0 * (1 - p0)) / n), where n represents the sample size. Substituting in your values, the z score will be calculated. This z-score can be used to find the p-value from a standard normal (Z) distribution table.
If the p-value is less than 0.05 (which is α, significance level), we reject the null hypothesis in favor of alternative hypothesis, else we do not reject the null hypothesis. Thus, our conclusion is formulated based on this p-value.
To construct a 95% confidence interval for the true proportion of vacant houses, we use the formula: p ± Z * sqrt((p * (1 - p)) / n). Here, Z will be the Z score corresponding to the desired confidence level, 95% (which is 1.96 for two-tailed test).
If the national proportion (0.114) doesn't lie within this interval, it supports our test conclusion of rejecting the null hypothesis and vice versa.
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A new drug to treat psoriasis has been developed and is in clinical testing. Assume that those individuals given the drug are examined before receiving the treatment and then again after receiving the treatment to determine if there was a change in their symptom status. If the initial results showed that 2.0% of individuals entered the study in remission, 77.0% of individuals entered the study with mild symptoms, 16.0% of individuals entered the study with moderate symptoms, and 5.0% entered the study with severe symptoms calculate and interpret a chi-squared test to determine if the drug was effective treating psoriasis given the information below from the final examination.
Answer:
Step-by-step explanation:
Solution:-
State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.
Null hypothesis: The distribution of severity of psoriasis cases at the end and prior are same.
Alternative hypothesis: The distribution of severity of psoriasis cases at the end and prior are different.
Formulate an analysis plan. For this analysis, the significance level is 0.05. Using sample data, we will conduct a chi-square goodness of fit test of the null hypothesis.
Analyze sample data. Applying the chi-square goodness of fit test to sample data, we compute the degrees of freedom, the expected frequency counts, and the chi-square test statistic. Based on the chi-square statistic and the degrees of freedom, we determine the P-value.
DF = k - 1 = 4 - 1
D.F = 3
(Ei) = n * pi
Category observed Num expected num [(Or,c -Er,c)²/Er,c]
Remission 380 20 6480
Mild
symptoms 520 770 81.16883117
Moderate
symptoms 95 160 24.40625
Severe
symptom 5 50 40.5
Sum 1000 1000 6628.075081
Χ2 = Σ [ (Oi - Ei)2 / Ei ]
Χ2 = 6628.08
Χ2Critical = 7.81
where DF is the degrees of freedom, k is the number of levels of the categorical variable, n is the number of observations in the sample, Ei is the expected frequency count for level i, Oi is the observed frequency count for level i, and Χ2 is the chi-square test statistic.
The P-value is the probability that a chi-square statistic having 3 degrees of freedom is more extreme than 6628.08.
We use the Chi-Square Distribution Calculator to find P(Χ2 > 19.58) =less than 0.000001
Interpret results. Since the P-value (almost 0) is less than the significance level (0.05), we cannot accept the null hypothesis.
We reject H0, because 6628.08 is greater than 7.81. We have statistically significant evidence at alpha equals to 0.05 level to show that distribution of severity of psoriasis cases at the end of the clinical trial for the sample is different from the distribution of the severity of psoriasis cases prior to the administration of the drug suggesting the drug is effective.
The chi-square test is a statistical method that determines if there's a significant difference between observed and expected frequencies in different categories, such as symptom status in this clinical trial. Without post-treatment numbers, we can't run the exact test. However, if the test statistic exceeded the critical value, we could conclude that the drug significantly affected symptom statuses.
Explanation:This question pertains to the use of a chi-squared test, which is a statistical method used to determine if there's a significant difference between observed frequencies and expected frequencies in one or more categories. For this case, the categories are the symptom statuses (remission, mild, moderate, and severe).
To conduct a chi-square test, you first need to know the observed frequencies (the initial percentages given in the question) and the expected frequencies (the percentages after treatment). As the question doesn't provide the numbers after treatment, I can't perform the exact chi-square test.
If the post-treatment numbers were provided, you would compare them to the pre-treatment numbers using the chi-squared formula, which involves summing the squared difference between observed and expected frequencies, divided by expected frequency, for all categories. The result is a chi-square test statistic, which you would then compare to a critical value associated with a chosen significance level (commonly 0.05) to determine if the treatment has a statistically significant effect.
To interpret a chi-square test statistic, if the calculated test statistic is larger than the critical value, it suggests that the drug made a significant difference in the distribution of symptom statuses. If not, we can't conclude the drug was effective.
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During the registration at the State University every semester, students in the college of business must have their courses approved by the college adviser. It takes the adviser an average of 2 minutes to approve each schedule, and students arrive at the adviser’s office at the rate of 28 per hour.17.How long does a student spend waiting on average for the adviser?A) 13 minutesB) 14 minutesC) 28 minutesD) 30 minutesE) none of the above
Answer:
Correct answer is option C i.e 28 minutes
Step-by-step explanation:
Number of students arriving at adviser's office per hour = x = 28
Number of students get approved = [tex]\frac{1}{2min}[/tex] = 30/hour
∴ y = 30
Number of students on average on waiting =Lq
Lq = [tex]\frac{x^{2} }{y(y-x)}[/tex]
= [tex]\frac{28^{2} }{30(30-28)}[/tex]
= 13.07
Average time student has to spend in
Waiting = Wq = [tex]\frac{x}{y(y-x)}[/tex]
= [tex]\frac{28}{30(30-28)}[/tex]
= 0.466 hours
= 28 minutes
In response to a survey question about the number of hours daily spent watching TV, the responses by the eight subjects who identified themselves as Hindu were 2 , 2 , 1 , 3 , 1 , 0 , 4 , 1
a. Find a point estimate of the population mean for Hindus.
--------------(Round to two decimal places as needed)
b. The margin of error at the 95% confidence level for this point estimate is 0.89. Explain what this represents.
The margin of error indicates we can be__%confident that the sample mean falls within __ of the _____(population mean/ standard error/ sample mean)
Answer:
a) [tex] \bar X = \frac{2+2+1+3+1+0+4+1}{8}= 1.75[/tex]
b) The margin of error indicates we can be 95%confident that the sample mean falls within 0.89 of the population mean
Step-by-step explanation:
Part a
The best point of estimate for the population mean is the sample mean given by:
[tex] \bar X = \frac{\sum_{i=1}^n X_i}{n}[/tex]
Since is an unbiased estimator [tex] E(\bar X) = \mu[/tex]
Data given: 2 , 2 , 1 , 3 , 1 , 0 , 4 , 1
So for this case the sample mean would be:
[tex] \bar X = \frac{2+2+1+3+1+0+4+1}{8}= 1.75[/tex]
Part b
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
[tex]\bar X[/tex] represent the sample mean for the sample
[tex]\mu[/tex] population mean (variable of interest)
s represent the sample standard deviation
n represent the sample size
The confidence interval for the mean is given by the following formula:
[tex]\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex] (1)
The margin of error is given by this formula:
[tex] ME=t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex] (2)
And for this case we know that ME =0.89 with a confidence of 95%
So then the limits for our confidence level are:
[tex] Lower= \bar X -ME= 1.75- 0.89=0.86[/tex]
[tex] Upperr= \bar X +ME= 1.75+0.89=2.64[/tex]
So then the best answer for this case would be:
The margin of error indicates we can be 95%confident that the sample mean falls within 0.89 of the population mean
Let M = {Λ,abb} and L = {bba,ab, a}, what is ML ? ML ={bba, abbbba,abbab,abbba, ab,a} ML ={bba, abbbba,abbab,abba, ab,a} ML ={bbab, abbbba,abbab,abba, ab,a} ML ={ba, abbbba,abbab,abba, ab,a}
Answer:
ML = {bba, ab, a, bbaabb, ababb, aabb}
Step-by-step explanation:
By application of Union of a set.
M = {bba,ab, a}
L = {Λ,abb}
ML = {bba, ab, a, bbaabb, ababb, aabb}
A dreidel is a four-sided spinning top with the Hebrew letters nun, gimel, hei, and shin, one on each side. Each side is equally likely to come up in a single spin of the dreidel. Suppose you spin a dreidel three times. Calculate the probability of getting: (a) at least one nun? (b) exactly 2 nuns? (c) exactly 1 hei? (d) at most 2 gimels?
So, the probabilities are: (a) 37/64, (b) 3/64, (c) 27/64, (d) 57/64
In each spin, there are four possible outcomes (nun, gimel, hei, shin), and each outcome is equally likely.
(a) Probability of getting at least one nun:
The probability of getting no nuns in a single spin is 3/4. So, the probability of getting no nuns in three spins is [tex](3/4)^3[/tex]. Therefore, the probability of getting at least one nun is 1 - [tex](3/4)^3[/tex].
Probability of getting at least one nun:
1 - [tex](3/4)^3[/tex] = [tex]1-\frac{27}{64}=\frac{37}{64}[/tex] = 0.58
(b) Probability of getting exactly 2 nuns:
The probability of getting a nun in a single spin is 1/4. So, the probability of getting exactly 1 hei in three spins is [tex]\left(\begin{array}{l}\frac{3}{1} \\\end{array}\right)\left(\frac{1}{4}\right)\left(\frac{3}{4}\right)^2[/tex].
= [tex]3 \times \frac{1}{16} \times \frac{3}{4}=\frac{3}{64}[/tex] = 0.05
(c) Probability of getting exactly 1 hei:
The probability of getting a hei in a single spin is 1/4. So, the probability of getting exactly 1 hei in three spins is [tex]\left(\begin{array}{l}\frac{3}{1} \\\end{array}\right)\left(\frac{1}{4}\right)\left(\frac{3}{4}\right)^2[/tex]
= [tex]3 \times \frac{1}{4} \times \frac{9}{16}=\frac{27}{64}[/tex] = 0.42
(d) Probability of getting at most 2 gimels:
The probability of getting 0 gimels is [tex](3/4)^3[/tex]. The probability of getting 1 gimel is [tex]\left(\begin{array}{l}\frac{3}{1} \\\end{array}\right)\left(\frac{1}{4}\right)\left(\frac{3}{4}\right)^2[/tex]. The probability of getting 2 gimels is [tex]\left(\begin{array}{l}\frac{3}{2} \\\end{array}\right)\left(\frac{1}{4}\right)^2\left(\frac{3}{4}\right)[/tex].
Add these probabilities to get the total probability.
[tex]\left(\frac{3}{4}\right)^3+\left(\begin{array}{l}\frac{3}{1} \\\end{array}\right)\left(\frac{1}{4}\right)\left(\frac{3}{4}\right)^2+\left(\begin{array}{l}\frac{3}{2} \\\end{array}\right)\left(\frac{1}{4}\right)^2\left(\frac{3}{4}\right)[/tex]
[tex]=\frac{27}{64}+\frac{27}{64}+\frac{3}{64}=\frac{57}{64}[/tex] = 0.9
Calculating probabilities of specific outcomes when spinning a dreidel multiple times.
Dreidel Probability Calculations:
(a) Probability of getting at least one nun: 1 - Probability of getting no nuns = 1 - [tex](3/4)^3[/tex].(b) Probability of getting exactly 2 nuns: Combination of outcomes with exactly 2 nuns / Total possible outcomes = (3 choose 2) x [tex](1/4)^2[/tex] x (3/4).(c) Probability of getting exactly 1 hei: Combination of outcomes with exactly 1 hei / Total possible outcomes = 3 x (1/4) x [tex](3/4)^2[/tex].(d) Probability of getting at most 2 gimels: Sum of probabilities of getting 0, 1, or 2 gimels.Find all the second order partial derivatives of g (x comma y )equalsx Superscript 4 Baseline y plus 5 sine (y )plus 4 y cosine (x ).
Answer:
Step-by-step explanation:
Check attachment for solution
Five players agree to divide a cake fairly using the last diminisher method. The players play in the following order: Anne first, Betty second, Cindy third, Doris fourth, and Ellen last. In round 1, there are no diminishers In round 2, Doris is the only diminisher In round 3, Cindy and Ellen are the only diminishers Which player gets her fair share at the end of:
Using the Last Diminisher method, in the first round, Anne gets her fair share because no one diminishes. In the second round, Doris is the only one who diminishes, thus gets her fair share. In the third round, despite Cindy and Ellen both diminishing, Ellen gets her fair share because she is later in turn order.
Explanation:The Last Diminisher method is a fair division protocol used when a divisible good, like a cake in this example, needs to be divided amongst several players. This method removes discrepancies by having each player in turn reduce the piece until they don't want to diminish it further, and then giving that piece to the last to diminish.
In this case, Anne, Betty, Cindy, Doris, and Ellen are dividing the cake and playing in that order. In the first round, no one diminishes, so Anne gets her fair share of the cake. In the second round, Doris is the only one who diminishes, so she gets her fair share at the end of this round. In the third round, the last to diminish are Cindy and Ellen, but since Ellen is later in order, Ellen is the one who gets her fair share at the end of the round.
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A 5-card hand is dealt from a well-shuffled deck of 52 playing cards. What is the probability that the hand contains at least one card from each of the four suits?
Answer:
0.2637
Step-by-step explanation:
We see from the question that the 5-card hand contains all 4 suits as shown below;
Number of cards = 52
Number of suits = 4
For the favorable cases therefore, we will choose two cards from the suit in which two cards are drawn. Then we will proceed to choose one card from each of the other suits.
4 suits will divide into 52 cards to give = (52 / 4) = 13 cards
Hence, the required probability;
[tex]= {\frac{4 *13c_2*13c_1*13c_1*13c_1}{52c_5}}\\= {\frac{2197}{8330}}\\= 0.2637[/tex]
An article reported on a school district's magnet schools program. Ofthe 1967 qualified applicants, 985 were accepted, 327 were waitlisted, and 655 were turned away for lack of space.a. The relative frequency of accepted qualified students (to three places after the decimal) is:________ b. The proportion of waitlisted students (to three places after the decimal) is:________ c. The percentage of students turned away from lack of space (to one place after the decimal) is:______
Answer:
a) 0.501
b) 0.166
c) 0.3
Step-by-step explanation:
We have the following information:
1967 qualified applicants
985 accepted
327 waitlisted
655 turned away for lack of space
a. The relative frequency of accepted qualified students (to three places after the decimal) is:________
This is the number of accepted qualified students divided by the number of qualified students.
So
985/1967 = 0.501
b. The proportion of waitlisted students (to three places after the decimal) is:________
This is the number of waitlisted students divided by the number of qualified students.
So
327/1967 = 0.166
c. The percentage of students turned away from lack of space (to one place after the decimal) is:______
This is the number of students turned away by lack of space divided by the number of qualified students.
So
655/1967 = 0.3
The relative frequency of accepted students is approximately 0.501, the proportion of waitlisted students is 0.166, and the percentage of students turned away for lack of space is roughly 33.3%.
Explanation:To find the relative frequency, proportion, and percentage from the given data for the school district's magnet schools program, we will use simple mathematical computations. We have a total of 1967 qualified applicants, where 985 were accepted, 327 were waitlisted, and 655 were turned away due to lack of space.
The relative frequency of accepted qualified students is calculated as the number of accepted students divided by the total number of applicants. So it's 985 / 1967 = 0.501 (to three places after the decimal).The proportion of waitlisted students is calculated as the number of waitlisted students divided by the total number of applicants. So it's 327 / 1967 = 0.166 (to three places after the decimal).The percentage of students turned away for lack of space is calculated as the number of students turned away divided by the total number of applicants, and then multiplied by 100 to convert it to a percentage. So it's (655 / 1967) * 100 ≈ 33.3% (to one place after the decimal).An algorithm takes 0.5 seconds to run on an input of size 100. How long will it take to run on an input of size 1000 if the algorithm has a running time that is linear? quadratic? log-linear? cubic?
Answer:
linear: 5s
quadratic: 50s
log-linear: 0.75 s
cubic: 500s
Step-by-step explanation:
Let [tex]t_1,t_2[/tex] be the running time associated with the input of sizes [tex] s_1,s_2[/tex]
If the running time is linear
[tex]t_2 = t_1\frac{s_2}{s_1} = 0.5*\frac{1000}{100} = 0.5*10 = 5s[/tex]
If the running time is quadratic
[tex]t_2 = t_1\left(\frac{s_2}{s_1}\right)^2 = 0.5*\left(\frac{1000}{100}\right)^2 = 0.5*10^2 = 50s[/tex]
If the running time is log-linear
[tex]t_2 = t_1\frac{log(s_2)}{log(s_1)} = 0.5*\frac{log(1000)}{log(100)} = 0.5*1.5 = 0.75s[/tex]
If the running time is cubic:
[tex]t_2 = t_1\left(\frac{s_2}{s_1}\right)^3 = 0.5*\left(\frac{1000}{100}\right)^3 = 0.5*10^3 = 500s[/tex]
The mean waiting time at the drive-through of a fast-food restaurant from the time the food is ordered to when it is received is 85 seconds. A manager devises a new system that he believes will decrease the wait time. He implements the new system and measures the wait time for 10 randomly sampled orders. They are provided below:
109 67 58 76 65 80 96 86 71 72
Assume the population is normally distributed.
(a) Calculate the mean and standard deviation of the wait times for the 10 orders.
(b) Construct a 99% confidence interval for the mean waiting time of the new system.
Answer:
a) And if we replace we got: [tex]\bar X= 78[/tex]
[tex] s = 15.391[/tex]
b) [tex]78-3.25\frac{15.391}{\sqrt{10}}=62.182[/tex]
[tex]78-3.25\frac{15.391}{\sqrt{10}}=93.818[/tex]
So on this case the 99% confidence interval would be given by (62.182;93.818)
Step-by-step explanation:
Dataset given: 109 67 58 76 65 80 96 86 71 72
Part a
For this case we can calculate the sample mean with the following formula:
[tex]\bar X = \frac{\sum_{i=1}^n X_i}{n}[/tex]
And if we replace we got: [tex]\bar X= 78[/tex]
And the deviation is given by:
[tex] s =\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}[/tex]
And if we replace we got [tex] s = 15.391[/tex]
Part b
The confidence interval for the mean is given by the following formula:
[tex]\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex] (1)
In order to calculate the critical value [tex]t_{\alpha/2}[/tex] we need to find first the degrees of freedom, given by:
[tex]df=n-1=10-1=9[/tex]
Since the Confidence is 0.99 or 99%, the value of [tex]\alpha=0.01[/tex] and [tex]\alpha/2 =0.005[/tex], and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,9)".And we see that [tex]t_{\alpha/2}=3.25[/tex]
Now we have everything in order to replace into formula (1):
[tex]78-3.25\frac{15.391}{\sqrt{10}}=62.182[/tex]
[tex]78-3.25\frac{15.391}{\sqrt{10}}=93.818[/tex]
So on this case the 99% confidence interval would be given by (62.182;93.818)
A department store surveyed 428 shoppers, and the following information was obtained: 216 shoppers made a purchase, and 294 were satisfied with the service they received. If 47 of those who made a purchase were not satisfied with the service, how many shoppers did the following?a. made a purchase and were satisfied with the service
b. made a purchase or were satisfied with the serice
c. were satisfied with the service but did not mak a purchase
d. were not satisfied and did not make a purchase
The answer are (a) 169 (b) 341 (c) 125 (d) 87
What is a Venn diagram?A Venn diagram is an illustration that uses circles to show the commonalities and differences between things or groups of things.
Given that, A department store surveyed 428 shoppers, and the following information was obtained: 216 shoppers made a purchase, and 294 were satisfied with the service they received. If 47 of those who made a purchase were not satisfied with the service,
Refer to the Venn diagram attached.
The total number of shoppers surveyed is, N = 428.
Number of shoppers who made a purchase, n (P) = 216
Number of shoppers who were satisfied with the service they received,
n (S) = 294
Number of shoppers who made a purchase but were not satisfied with the service, n(S' ∩ P) = 47
(a) The number of shoppers who made a purchase and were satisfied with the service = n(S ∩ P)
n(S ∩ P) = n(P)-n(S'∩P)
= 216 - 47 = 169
(b) The numbers of shoppers who made a purchase or were satisfied with the service = n (P ∪ S)
n (P ∪ S) = n(P)+n(S)-n(S∩P)
= 216+294-169
= 341
(c) The numbers of shoppers who were satisfied with the service but did not make a purchase = n(S∩P')
= n(S)-n(S∩P)
= 241-169
= 125
(d) The number of shoppers who were not satisfied and did not make a purchase = n(S'∩P')
= N-n (S ∪ P)
= 428-341
= 87
Hence, the answer are (a) 169 (b) 341 (c) 125 (d) 87
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a. 169 shoppers made a purchase and were satisfied with the service.
b. 341 shoppers made a purchase or were satisfied with the service.
c. 125 shoppers were satisfied with the service but did not make a purchase.
d. 381 shoppers were not satisfied and did not make a purchase.
Let's break down the information given:
Total shoppers surveyed = 428
Shoppers who made a purchase = 216
Shoppers satisfied with the service = 294
Shoppers who made a purchase and were not satisfied = 47
We are asked to find:
a. Shoppers who made a purchase and were satisfied with the service.
To find this, we subtract the shoppers who made a purchase and were not satisfied from the total shoppers who made a purchase:
216 − 47 = 169
b. Shoppers who made a purchase or were satisfied with the service.
To find this, we add the shoppers who made a purchase and the shoppers who were satisfied, but we need to be careful not to count the overlap twice (those who made a purchase and were satisfied):
216+294−169=341
c. Shoppers who were satisfied with the service but did not make a purchase.
To find this, we subtract the shoppers who made a purchase and were satisfied from the total shoppers who were satisfied:
294−169=125
d. Shoppers who were not satisfied and did not make a purchase.
To find this, we subtract the shoppers who made a purchase and were not satisfied from the total shoppers surveyed:
428−47=381
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Given two dependent random samples with the following results: Population 1 58 76 77 70 62 76 67 76 Population 2 64 69 83 60 66 84 60 81 Can it be concluded, from this data, that there is a significant difference between the two population means? Let d=(Population 1 entry)−(Population 2 entry). Use a significance level of α=0.01 for the test. Assume that both populations are normally distributed.
Answer:
[tex]z=\frac{\bar d -0}{\frac{\sigma_d}{\sqrt{n}}}=\frac{-0.625 -0}{\frac{6.818}{\sqrt{8}}}=-0.259[/tex]
[tex]p_v =2*P(z<-0.259) =0.796[/tex]
So the p value is higher than the significance level given [tex]\alpha=0.01[/tex], then we can conclude that we FAIL to reject the null hypothesis that the difference mean between after and before is equal to 0. So we can conclude that we don't have significant differences between the two populations.
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
Solution to the problem
Let's put some notation :
x=values popoulation 2 , y = values population 1
x: 64 69 83 60 66 84 60 81
y: 58 76 77 70 62 76 67 76
The system of hypothesis for this case are:
Null hypothesis: [tex]\mu_y- \mu_x = 0[/tex]
Alternative hypothesis: [tex]\mu_y -\mu_x \neq 0[/tex]
The first step is calculate the difference [tex]d_i=y_i-x_i[/tex] and we obtain this:
d: -6,7,-6,10,-4,-8, 7, -5
The second step is calculate the mean difference
[tex]\bar d= \frac{\sum_{i=1}^n d_i}{n}= \frac{-5}{8}=-0.625[/tex]
The third step would be calculate the standard deviation for the differences, and we got:
[tex]\sigma_d =\frac{\sum_{i=1}^n (d_i -\bar d)^2}{n} =6.818[/tex]
The 4 step is calculate the statistic given by :
[tex]z=\frac{\bar d -0}{\frac{\sigma_d}{\sqrt{n}}}=\frac{-0.625 -0}{\frac{6.818}{\sqrt{8}}}=-0.259[/tex]
Now we can calculate the p value, since we have a two tailed test the p value is given by:
[tex]p_v =2*P(z<-0.259) =0.796[/tex]
So the p value is higher than the significance level given [tex]\alpha=0.01[/tex], then we can conclude that we FAIL to reject the null hypothesis that the difference mean between after and before is equal to 0. So we can conclude that we don't have significant differences between the two populations.
Euclidean distance can be used to calculate the dissimilarity between two observations. Let u = (25, $350) correspond to a 25-year-old customer that spent $350 at Store A in the previous fiscal year. Let v = (53, $420) correspond to a 53-year-old customer that spent $4,100 at Store A in the previous fiscal year. Calculate the dissimilarity between these two observations using Euclidean distance.
a. 66.21
b. 88.57
c. 72.28
d. 75.39
Answer:
Option D
75.39
Step-by-step explanation:
When provided with the co-ordinates (x, y) and(a, b) then the distance between them is given by [tex]\sqrt {(x-a)^{2}+(y-b)^{2}}[/tex]
Since u = (25, $350) and v = (53, $420) then the Euclidean distance will be
[tex]\sqrt {(53-25)^{2}+(350-420)^{2}}=75.3923073\approx 75.39[/tex]
The dissimilarity between the two observations using Euclidean distance is approximately 75.39(Option d).
Explanation:To calculate the dissimilarity between two observations using Euclidean distance, we need to find the distance between the corresponding elements in the two observations and then calculate the square root of the sum of their squared differences.
In this case, we have:
u = (25, $350) and v = (53, $420)
The distance between the ages is 53 - 25 = 28.
The distance between the amounts spent is $420 - $350 = $70.
Now we can use the formula for Euclidean distance:
Distance = sqrt((28)^2 + (70)^2) = sqrt(784 + 4900) = sqrt(5684) ≈ 75.39
Therefore, the dissimilarity between the two observations using Euclidean distance is approximately 75.39.
Learn more about Euclidean distance here:
https://brainly.com/question/30930235
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