1. In a hypothesis test comparing two population means, the equal 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) at least one standard deviation is larger than 10.
3. For the hypothesis, H0: µ1 ≤ µ2, 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, H0: µ1 ≤ µ2 (.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 of the means for two independent populations (population standard deviations unknown), what should be true?
A) At least one standard deviation is larger than 10.
B) Both populations are normally distributed.
C) The samples sizes selected from each population must be equal.
D) Both B and C.
6. To conduct a test of means for two independent populations, which of the following is required?
A) The z-statistic is the test statistic.
B) The t-statistic is the test statistic.
C) At least one standard deviation is larger than 10.
D) Sampling from the two populations must be random.
7. Another way to state the null hypothesis, H0: µ1 = µ2, is:
A) H0: µ1 ≤ µ2
B) H0: µ1 - µ2 = 0
C) H0: µ1 ≥ µ2
D) H0: µ1 - µ2 ≠ 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) at least one standard deviation is larger than 10.
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) None of the above.
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. To test H0: µ1 = µ2 using a significance level of 0.05, a z-test statistic of 2.06 was computed. Based on the p-value,
A) Accept the null hypothesis.
B) Fail to reject the null hypothesis.
C) Reject the null hypothesis.
D) Reject the alternative hypothesis.
12. To test H0: µ1 ≤ µ2 using a significance level of 0.05, a z-statistic of 1.55 was computed. Based on a p-value,
A) The null hypothesis is accepted.
B) Fail to reject the null hypothesis.
C) Reject the null hypothesis.
D) Reject the alternative hypothesis.
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, H0: µ1 = µ2, populations are:
A) independent.
B) dependent.
C) unrelated.
D) equal.
14. A company is interested in investigating 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, H0: µ1 = µ2, the test statistic is the:
A) z distribution.
B) t distribution with 49 degrees of freedom.
C) t distribution with 23 degrees of freedom.
D) t distribution with 50 degrees of freedom.