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```					                                         Chapter 9 Practice Test A

Name: __________________________ Date: _____________

Use the following to answer questions 1-2:

A sociologist wants to determine if the life expectancy of people in Africa is less than the life
expectancy of people in Asia. The data obtained is shown in the table below.

Africa       Asia
X       55.3         65.2
       8.1          9.3
n       53           42

1. What is the null hypothesis? Use   0.05 .

A) H0 : 1   2    B) H0 :  1   2   C) H0 :  1   2      D) H0 :  1   2

2. Calculate the critical value. Use   0.05 .

A) –1.96     B) –2.58       C) –1.65      D) –2.33

3. When testing the difference between two proportions, one sample had 30 out of 100
who were for capital punishment and the other sample had 60 out of 80 who were for
capital punishment. Calculate the standard error.

A) 0.060     B) 0.042       C) 0.098      D) 0.075

4. Determine the 95% confidence interval of the true difference in the means. A sociologist
wants to determine if the life expectancy of people in Africa is less than the life
expectancy of people in Asia. The data obtained is shown in the table below. Use
  0.05 .
Africa     Asia
X         55.3       65.2
          8.1        9.3
n          53         42

A) 16.33  1   2  5.98                       C)       13.46  1   2  6.34
B) 1216  1   2  6.86
.                                           D)       1135  1   2  7.58
.

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Chapter 9 Practice Test A

5. The campus bookstore asked a random set of freshmen and seniors as to how much they
spent on textbooks in that term. The bookstore believes that the two groups spend the
same amount. What is the test value?
Freshmen                Seniors
Sample size                        70                    40
Mean spending                      40                    45
Sample variance                   400                   700

A) –1.04    B) –1.75    C) 4.82    D) –0.22

6. If s1  12.31 and F  2.13 , what is the value of s2 as shown in the figure below?

A) 8.43    B) 17.97     C) 5.78     D) 71.14

7. A car salesman claims that the variance of prices on convertibles is higher than the
variance on station wagons. The standard deviation of 16 convertibles is \$6800 and the
standard deviation of 24 station wagons is \$3900. For   0.05 , what is the test value?

A) 3.04    B) 2.78     C) 2.33    D) 3.00

8. A recent survey reported that in a sample of 300 students who attend two-year colleges,
105 work at least 20 hours a week. In a sample of 225 students attending private
universities, only 20 students work at least 20 hours per week. What is the test value?

A) 7.61    B) 2.38     C) 4.18    D) 6.95

9. What is the critical value for a two-tailed F -test with   010 , when the sample size
.
from which the variance for the numerator was obtained was 10, and the sample size
from which the denominator was obtained was 24?

A) 2.25    B) 2.32     C) 2.30    D) 2.27

Page 2
Chapter 9 Practice Test A

Use the following to answer question 10:

Mauricio Cruz, a wine merchant for Cruz's Spirits Emporium, wants to determine if the average
price of imported wine is less than the average price of domestic wine. The data obtained is
shown in the table below.

Imported Wine          Domestic Wine
X     7.03                     9.78
s     2.31                     3.62
n     15                       16

10. What is the critical value? Use   0.05 .

A) –1.703     B) –1.761     C) –2.045        D) –1.697

11. Many elementary school students in a school district currently have ear infections. A
random sample of children in two different schools found that 15 of 46 at one school
and 21 of 38 at the other had this infection. At the .05 level of significance, is there
sufficient evidence to conclude that a difference exists between the proportion of
students who have ear infections at one school and the other?

A) Yes, there is sufficient information to reject the hypothesis that the proportions of
students at the two schools who have ear infections are the same because the test
value –10.67 is outside the acceptance region (-1.96,1.96).
B) Yes, there is sufficient information to reject the hypothesis that the proportions of
students at the two schools who have ear infections are the same because the test
value –19.25 is outside the acceptance region (-1.96,1.96).
C) Yes, there is sufficient information to reject the hypothesis that the proportions of
students at the two schools who have ear infections are the same because the test
value –2.09 is outside the acceptance region (-1.96,1.96).
D) Yes, there is sufficient information to reject the hypothesis that the proportions of
students at the two schools who have ear infections are the same because the test
value –2.74 is outside the acceptance region (-1.96,1.96).

Page 3
Chapter 9 Practice Test A

12. 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 effectivess for women and for men. At α = .05, what is the test value?
Women                Men
Sample size                           40                  60
Mean effect                           7.5                7.05
Sample variance                        3                   5

A) 1.13    B) 2.84     C) 0.40     D) 0.88

13. Determine the value of  as shown in the figure below, if the degrees of freedom were
seven and nine.

A) 0.025     B) 0.05     C) 0.1      D) 0.01

14. If the test value in the figure below, for a test of the difference between two large
sample means, is 2.57 when the critical value is 1.96, what decision about the

A) reject the alternative hypothesis               C) not enough information
B) reject the null hypothesis                      D) accept the null hypothesis

Page 4
Chapter 9 Practice Test A

15. In comparing the two standard deviations below, what is the test value and what are the
degrees of freedom that should be used?
Standard Deviation Number of values
Sample 1                        5                  18
Sample 2                        3                  26

A)   test value = 1.67, degrees of freedom = 17 and 25
B)   test value = 2.78, degrees of freedom = 18 and 26
C)   test value = 2.78, degrees of freedom = 17 and 25
D)   test value = 1.67, degrees of freedom = 18 and 26

16. A running coach wanted to see whether runners ran faster after eating spaghetti the night
before. 20 random runners were chosen for this study. They ran a 5 kilometer race after
having a normal dinner the night before, and then a week later, reran the same race after
having a spaghetti dinner the night before. Their results (in seconds) are in the table
below. At α = .01, what is the test value to use for this test?
Regular Dinner      Spaghetti        Difference
Dinner          by runner
Sample mean                        1100              1085              –15
Sample variance                    2200              2200              500

A) –3.00    B) –3.72    C) –0.67    D) –0.23

17. Find p and q when X 1 =16, n1 =60, X 2 =25, and n2 =60

A) p = 2.93 and q = 1.52                        C) p = 0.66 and q = 0.34
B) p = 1.52 and q = 2.93                        D) p = 0.34 and q = 0.66

Page 5
Chapter 9 Practice Test A

Use the following to answer questions 18-20:

A researcher wanted to determine if using an octane booster would increase gasoline mileage. A
random sample of seven cars was selected; the cars were driven for two weeks without the
booster and two weeks with the booster.

Miles / Gal Without           Miles / Gal With
21.2                          23.8
25.4                          25.6
20.9                          22.4
27.6                          28.3
22.8                          24.5
27.3                          28.8
23.4                          25.2

18. State the alternative hypothesis?

A) H1:  D  0    B) H1:  D  0      C) H1:  D  0    D) H1:  D  0

19. What is the critical value using   0.05 ?

A) -1.895      B) -1.943     C) -1.782     D) -1.761

20. Determine the mean of the difference.

A) –1.43     B) 1.43       C) –0.96     D) –6.3

Page 6
Chapter 9 Practice Test A

1.   A
2.   C
3.   D
4.   C
5.   A
6.   A
7.   A
8.   D
9.   B
10.   B
11.   C
12.   A
13.   A
14.   B
15.   B
16.   A
17.   D
18.   D
19.   B
20.   A

Page 7

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