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4 years ago
Q-Mart is interested in comparing its male and female customers. Q-Mart would like to know if the amount of money spent by its female charge customers differs, on average, from the amount spent by its male charge customers. To answer this question, an analyst collected random samples of 25 female customers and 22 male customers.

Based on these samples, on average, the 25 women charge customers spent $102.23 and the 22 men charge customers spent $86.46. Moreover, the sample standard deviation of the amount charged by the 25 women was $93.393, and the sample standard deviation of the amount charged by the 22 men was $59.695.

Suppose, using a 10% level of significance, you wish to know if there is sufficient evidence for Q-Mart to conclude that, on average, the amount spent by women charge customers differs from the amount spent by men charge customers. That is suppose you wish to test

H0:   versus  H1:

Assuming that the amounts spent by male and female charge customers at Q-Mart are normally distributed, based on the procedure advocated by Bluman, what is the test value that you would use to conduct this test of hypothesis? Place your answer, rounded to 3 decimal places, in the blank. For example, 0.123 would be a legitimate entry.   
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4 years ago
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Here are two critical values because of the word "differs". If they wanted to know whether women spend more than men, for example, then it would have been a one-tailed test.

To find the critical values you first have to calculate the degrees of freedom. It's a big, ugly formula, but I will evaluate it in parts here.

The numerator of df is:

[93.393^2/25 + 59.695^2/22]^2 = 260985.1465

The denominator of df is:

(93.393^2/25)^2 / (25-1) + (59.695^2/22)^2 / (22-1) = 6321.204622

df = 260985.1465 / 6321.204622 = 41.287,

which rounds down to 41.

Because this is a two-tailed test at 10%, we need 5% in each tail. My t-table only has df = 40, (not df = 41), so this answer will be approximate, but close:

critical values = +/- 1.684
This verified answer contains over 120 words.
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wrote...
4 years ago
Thank you again and also thank you for the explanation Slight Smile. That way I understand the process as well ..

Krestik
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Educator
4 years ago
No worries!
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4 years ago
Good Afternoon Bio_man,

   I know I ve been bugging you all week already but you seem to know what you talking about.
I ve been trying to solve a couple of my questions ALL SATURDAY MORNING AND FRIDAY NIGHT but I have a huge problem with the following ones;

Is there any way you could explain the process with the answer? I would greatly appreciate that:


A pharmaceutical company is testing the effectiveness of a new drug for lowering cholesterol. As part of this trial, they wish to determine whether there is a difference between the effectiveness for women and for men.  Assume α = 0.05.  What is the test value?
 
Women
Men
Sample size
50
80
Mean effect
7
6.95
Sample variance
3
4
 A.z = 0.455   
 B.t = 0.151   
 C.t = 3.252   
 D.z = 0.081   

Data for a sample of 25 apartments in a particular neighborhood are provided in the worksheet Apartments in the Excel workbook Apartments.xlsx. Using the estimated regression equation found by using size as the predictor variable, find a point estimate for the average monthly rent for apartments having 1,000 square feet of space. Place your answer, rounded to the nearest whole dollar, in the blank.    When entering your answer do not use any labels or symbols. Simply provide the numerical value. For example, 123 would be a legitimate entry.


The marketing manager of a large supermarket chain would like to determine the effect of shelf space (in feet) on the weekly sales of international food (in hundreds of dollars). A random sample of 12 equal –sized stores is selected, with the following results:

Store   Shelf Space(X)   Weekly Sales(Y)
1   10   2.0
2   10   2.6
3   10   1.8
4   15   2.3
5   15   2.8
6   15   3.0
7   20   2.7
8   20   3.1
9   20   3.2
10   25   3.0
11   25   3.3
12   25   3.5
Based on these data, what are the least squares regression coefficients of the Y-intercept (a) and slope (b)?

Place your answers, rounded to 3 decimal places , in the blanks provided.

a =            b = 

Are America's top chief executive officers (CEOs) really worth all that money? One way to answer this question is to look at the annual company percentage increase in revenue versus the CEO's annual percentage salary increase in that same company. Suppose that a random sample of companies yielded the following data:

percent change for corporation   15   12   3   12   28   6   8   2
percent change for CEO   6   17   -4   12   32   -1   7   2



Do these data indicate that the population mean percentage increase in corporate revenue is greater than the population mean percentage increase in CEO salary? Use a 5% level of significance. What is the test value that you would use to conduct this test of hypothesis?  Place your answer, rounded to 3 decimal places, in the blank.  For example, 2.345 would be a legitimate entry.   

A professor gives an exam for which there are two versions, A and B.  Each student in the class is given one randomly selected version of the exam.   After the exam, the professor wishes to determine if there is a difference in the level of difficulty of the two versions by determining if there is a significant difference in the mean scores.  Assume α = 0.05.

 
Version A
Version B
Sample size
45
65
Mean score
8.8
8.2
Sample variance
2.6
2.4

What is the test value for this hypothesis test?

Answer:     Round your answer to two decimal places.

What is/are the critical value(s) for this hypothesis test?  If there are two critical values, give only the positive value.

Answer:      Round your answer to two decimal places.

What is the conclusion for this hypothesis test?  Choose one.

1.  There is not sufficient evidence to show that one version of the exam is more difficult than the other.
2.  There is sufficient evidence to show that one version of the exam is more difficult than the other.

Answer:      Enter only a 1 or 2 for your answer.

I just don't get it Frowning FaceFrowning FaceFrowning Face

Krestik
wrote...
Educator
4 years ago
D.z = 0.081

Answer to the first question. Please keep in mind the rules when posting new threads. I deleted your other thread since you disregarded what I told you in the past.
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