Multiple choice problems based on the test of single population mean.
1. Assume that in a hypothesis test with null hypothesis 0 μ H : = 13.0 at a = 0.05, that a value of 11.0 for the sample mean results in the null hypothesis not being rejected. That corresponds to a confidence interval result of
i. The 95% confidence interval for the mean does not contain the value 13.0
ii. The 95% confidence interval for the mean contains the value 11.0
iii. There is insufficient information to conclude whether the 95% confidence interval for the mean contains or does not contain the value 13.0
iv. The 95% confidence interval for the mean contains the value 13.0
2. Nationwide, the average waiting time until electric utility customer service representative answers a call is 300 seconds per call. The Gigantic Kilowatt Energy Company took a sample of 35 calls and found that, on the average, they answered in 240 seconds per call with the standard deviation of 50. Can the company claim that they are faster than the average utility?
a. No, because -0.20 falls in the critical region
b. Yes, because -7.10 falls in the critical region
c. No, because -1.20 falls in the critical region
d. Yes, because -0.20 falls in the critical region
3. If the observed value is 4, the expected value is 5, and the standard error is 4, then the test value used for the z test is equal to
a.-1.00
b.0.25
c.-0.25
d.1.00
4. Using the z table in Table E of Appendix C, what are the critical values for a two-tailed test while a = 0.03.
a.± 2.17
b.± 2.05
c.± 2.33
d. ± 1.88
5. The average speed of greyhound dogs is about 18.8 meters per second. A particular greyhound breeder claims that her dogs are faster than the average greyhound. In a sample of 45 of her dogs, they ran, on the average, 19.2 meters per second with a standard deviation of 1.4. Is her claim accurate if she is willing to accept an error rate of 2.5 out of 100?
a. Yes, because 1.92 falls in the noncritical region
b. No, because 0.04 falls in the noncritical region
c. Yes, because 0.04 falls in the noncritical region
d. No, because 1.92 falls in the noncritical region
6. What is the critical t-value for a right-tailed test when a = .025and d.f. = 12?
i.0.695
ii.2.179
iii.2.831
iv.2.201