Practice Test 4 Final Fall 2009 Venable Statistics
(Answer key will be on http://www.cabrillo.edu/~evenable)
Please show all work – even work done by calculator.
NAME_____________
1. The marketing manager for a software company is trying to decide whether to market her
company’s newest product by mail, on television, or through the Internet. She selects 20
communities in which to test-market the product, advertising through one of the three media in
each community. The following table shows the amount of sales, in hundreds of dollars for each
community:
Mail
6
8
10
6
9
5
4
TV
9
11
9
14
4
7
Internet
16
11
12
8
9
15
10
Sales are normally distributed and the standard deviations are equal for all three methods of
advertising. Test if the means are the same for all three treatments at the 2.5% significance level.
2. The following table lists the number of computers sold at a computer store on each day of the
week for a sample of 10 weeks.
Days of the Week
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Computers Sold
18
24
26
28
25
46
43
Using the 1% significance level, test the null hypothesis that the number of computers sold at this store
on each day of the week is the same.
3. A sample of 500 drivers indicated whether or not they exceeded the speed limit while driving.
The following table gives a two-way classification for these 500 drivers.
Gender
Male
Female
Speed
222
136
Never Speed
70
72
Test at the 1% significance level if gender and speeding are related.
4. A school newspaper secured two samples: one of 500 non-player college students and another of
200 player college students. These students indicated whether the educational requirements for
player college students should be restricted. The following table gives a two-way classification
for the responses of these students.
Non-player
Player
Restrict
385
70
Do Not Restrict
115
130
Test at the 2.5% significance level if the distributions of opinion about restricting and not restricting the
educational requirements for player college students are the same for non-player and player students.
5. The following table lists the amount (in millions of dollars) spent on advertising and the total
sales (in millions of dollars) in year 2000 for a sample of six corporations.
Advertising Expenditure
5.0
3.5
1.5
6.5
2.0
8.5
Total Sales
47
55
23
74
26
85
a. Construct a scatter diagram for these data.
b. Find the equation for the least squares regression line with advertising expenditure as an
independent variable and total sales as a dependent variable. Show your work and all subtotals.
c. Give a brief interpretation of the values of a and b.
d. Predict the year 2000 total sales of a corporation that spent $7 million on advertising.