BSTAT2 2nd Edition By Gerald Keller – Test Bank

CHAPTER 11: INFERENCE ABOUT A POPULATION

TRUE/FALSE

1. In order to determine the p-value associated with hypothesis testing about the population mean , it is necessary to know the value of the test statistic.

ANS: T NAT: Analytic; Hypothesis Testing

2. In order to interpret the p-value associated with hypothesis testing about the population mean , it is necessary to know the value of the test statistic.

ANS: F NAT: Analytic; Hypothesis Testing

3. If a sample has 15 observations and a 95% confidence estimate for  is needed, the appropriate value of t is 1.753.

ANS: F NAT: Analytic; Hypothesis Testing

4. If a sample has 18 observations and a 90% confidence estimate for  is needed, the appropriate value of t is 1.740.

ANS: T NAT: Analytic; Hypothesis Testing

5. The statistic when the sampled population is normal is Student t-distributed with n degrees of freedom.

ANS: F NAT: Analytic; Hypothesis Testing

6. If the sampled population is nonnormal, the t-test of the population mean  is still valid, provided that the condition is not extreme.

ANS: T NAT: Analytic; Hypothesis Testing

7. A race car driver tested his car for time from 0 to 60 mph, and in 20 tests obtained an average of 48.5 seconds with a standard deviation of 1.47 seconds. A 95% confidence interval for the 0 to 60 time is 45.2 seconds to 51.8 seconds.

ANS: F NAT: Analytic; Hypothesis Testing

8. In forming a 95% confidence interval for a population mean from a sample size of 20, the number of degrees of freedom from the t-distribution equals 20.

ANS: F NAT: Analytic; Hypothesis Testing

9. The t-distribution is used in a confidence interval for a mean when the actual standard error is not known.

ANS: T NAT: Analytic; Hypothesis Testing

10. The t-distribution allows the calculation of confidence intervals for means for small samples when the population variance is not known, regardless of the shape of the distribution in the population.

ANS: F NAT: Analytic; Hypothesis Testing

11. The t-distribution is used to develop a confidence interval estimate of the population mean when the population standard deviation is unknown.

ANS: T NAT: Analytic; Hypothesis Testing

12. The t-distribution assumes that the population is normally distributed.

ANS: T NAT: Analytic; Hypothesis Testing

13. In estimating the population mean with the population standard deviation unknown, if the sample size is 16, there are 8 degrees of freedom.

ANS: F NAT: Analytic; Hypothesis Testing