The correct answer for each question is indicated by a .

1

In a hypothesis test comparing two population means, the "=" sign always appears in the:

A)

null hypothesis.

B)

alternate hypothesis.

C)

upper tail of the test statistic.

D)

lower tail of the test statistic.

2

In a hypothesis test comparing two population means, we use the z distribution when:

A)

the two population standard deviations are equal.

B)

both populations have at least 4000 observations.

C)

both population standard deviations are known.

D)

nπ and n(1-π) are both greater than 5.

3

For the hypothesis, H_{0}: µ_{1} ≤ µ_{2}, a random sample of 10 observations is selected from the first normal population and 8 from the second normal population. What is the number of degrees of freedom?

A)

18

B)

17

C)

16

D)

9

4

For the hypothesis, H_{0}: µ_{1} ≤ µ_{2}, (.01 significance level), a random sample of 10 observations is selected from the first normal population and 8 from the second normal population. Population standard deviations are unknown. What is (are) the critical value(s)?

A)

2.583

B)

-2.921, 2.921

C)

-2.583, 2.583

D)

-2.583

5

When testing a hypothesis about the means for two independent populations (population standard deviations unknown), what should be true?

A)

nπ and n(1-π) are both greater than 5.

B)

Both populations are normally distributed.

C)

The samples sizes selected from each population must be equal.

D)

The observations are matched or paired.

6

To conduct a test of means for two independent populations, which of the following is required?

A)

A z-statistic is used to test the hypothesis.

B)

The population standard deviations must be equal.

C)

nπ and n (1 - π) must be 5 or greater.

D)

A one-tailed hypothesis test.

7

Another way to state the null hypothesis: H_{0}: µ_{1} = µ_{2}, is:

A)

H_{0}: µ_{1} ≤ µ_{2}

B)

H_{0}: µ_{1} - µ_{2} = 0

C)

H_{0}: µ_{1} ≥ µ_{2}

D)

H_{0}: µ_{1} - µ_{2 }≠ 0

8

To conduct a test of hypothesis for dependent populations, we assume that:

A)

the distribution of the difference between the sampled paired observations follows the normal distribution.

B)

both samples are at least 30.

C)

the samples are unrelated.

D)

nπ and n(1-π) are both greater than 5.

9

When conducting a test of hypothesis for dependent samples:

A)

the sample size should be at least 30 pairs of observations.

B)

the significance level is more than .05.

C)

the p-value is more than .10.

D)

differences between each matched pair of observations are computed.

10

Which of the following is necessary to determine a p-value?

A)

Knowledge of whether the test is one-tailed or two-tailed

B)

The value of the test statistic

C)

The level of significance

D)

Both A and B

11

A z-test statistic of 2.06 was computed to test: H_{0}: µ _{1} = µ _{2}, using a significance level of 0.05. What is the p-value?

A)

2.0600

B)

0.0394

C)

0.0197

D)

0.4803

12

A z-statistic of 1.55 was computed to test H_{0}: µ _{1} ≤ µ _{2,} using a significance level is 0.05. What is the p-value?

A)

0.0500

B)

1.5500

C)

0.4394

D)

0.0606

13

A company is interested in knowing the effects of a computer-training program. The company randomly selected 25 employees and measured their computer skills before and after the training program. To test the hypothesis, H_{0}: µ _{1} = µ _{2}, the populations are:

A)

independent.

B)

dependent.

C)

unrelated.

D)

equal.

14

A company is interested in knowing the effects of a computer-training program. The company randomly selected 25 employees and measured their computer skills before and after the training program. To test the hypothesis, H_{0}: µ _{1} = µ _{2}, the test statistic is a:

A)

z-statistic.

B)

t-statistic with 49 degrees of freedom.

C)

t-statistic with 23 degrees of freedom.

D)

chi-square statistic with 23 degrees of freedom.

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