This

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Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1.
The level of significance
a.
can be any positive value
b.
can be any value
c.
is (1 - confidence level)
d.
can be any value between -1.96 to 1.96
____
2.
The average life expectancy of tires produced by the Whitney Tire Company has been 40,000 miles.
Management believes that due to a new production process, the life expectancy of their tires has increased. In
order to test the validity of their belief, the correct set of hypotheses is
a.
H
0
:
μ
< 40,000
H
a
:
μ
≥
40,000
b.
H
0
:
μ
≤
40,000
H
a
:
μ
> 40,000
c.
H
0
:
μ
> 40,000
H
a
:
μ
≤
40,000
d.
H
0
:
μ
≥
40,000
H
a
:
μ
< 40,000
Exhibit 9-1
n = 36
= 24.6
S = 12
H
0
:
μ
≤
20
H
a
:
μ
> 20
____
3.
Refer to Exhibit 9-1. If the test is done at 95% confidence, the null hypothesis should
a.
not be rejected
b.
be rejected
c.
Not enough information is given to answer this question.
d.
None of these alternatives is correct.
Exhibit 9-3
n = 49
= 54.8
s = 28
H
0
:
μ
= 50
H
a
:
μ
≠
50
____
4.
Refer to Exhibit 9-3. The p-value is equal to
a.
0.1151
b.
0.3849
c.
0.2698
d.
0.2302
____
5.
Refer to Exhibit 9-3. If the test is done at the 5% level of significance, the null hypothesis should
a.
not be rejected
b.
be rejected
c.
Not enough information given to answer this question.
d.
None of these alternatives is correct.
1

Exhibit 9-4
The manager of a grocery store has taken a random sample of 100 customers. The average length of time it
took the customers in the sample to check out was 3.1 minutes with a standard deviation of 0.5 minutes. We
want to test to determine whether or not the mean waiting time of all customers is significantly more than 3
minutes.
____
6.
Refer to Exhibit 9-4. The standardized test statistic is
a.
1.96
b.
1.64
c.
2.00
d.
0.056
____
7.
For a two-tailed test at 86.12% confidence, Z =
a.
1.96
b.
1.48
c.
1.09
d.
0.86
____
8.
For a one-tailed test (upper tail), a sample size of 18 at 95% confidence, t =
a.
2.12
b.
-2.12
c.
-1.740
d.
1.740
Exhibit 9-6
A random sample of 16 students selected from the student body of a large university had an average age of 25
years and a standard deviation of 2 years. We want to determine if the average age of all the students at the
university is significantly different from 24. Assume the distribution of the population of ages is normal.
____
9.
Refer to Exhibit 9-6. At 95% confidence, it can be concluded that the mean age is
a.
not significantly different from 24
b.
significantly different from 24
c.
significantly less than 24
d.
significantly less than 25
____
10.
For a one-tailed test (lower tail) at 89.8% confidence, Z =
a.
-1.27
b.
-1.53
c.
-1.96
d.
-1.64
____
11.
For a one-tailed test (upper tail), a sample size of 26 at 90% confidence, t =
a.
1.316
b.
-1.316
c.
-1.740
d.
1.740
____
12.
For a one-tailed test (lower tail), a sample size of 22 at 95% confidence, t =
a.
-1.383
b.
1.383
c.
-1.717
d.
-1.721
2

____
13.
Which of the following statements is

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