Hypothesis Testing, Test statistic, Z or T test

1) The owner of a local night club has recently surveyed a random sample of n=250 customers of the club. She would now like to determine whether or not the mean age of her customers is over 30. If so, she plans to alter the entertainment to appeal to an older crowd. If not, no entertainment changes will be made. If so, she plans to alter the entertainment to appeal to an older crowd. If not, no entertainment changes will be made. The appropriate hypotheses to test are

a) Ho: population mean is greater than or equal to 30 versus H1: population mean is less than 30
b) Ho: population mean is less than or equal to 30 versus H1: population mean is greater than 30
c) Ho: sample mean is greater than or equal to 30 versus H1: sample mean is less than 30
d) Ho: sample mean is greater than or equal to 30 versus H1: sample mean is greater than 30

2) How many Kleenex should the Kimberly clark Copr package of tissues contain? Researchers determined that 60 tissues is the average number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: sample mean = 52, s = 22 Suppose the test statistic does fall in the rejection region at a = 0.05. Which of the following decisions is correct?

a. At ? = 0.05, we reject H0.
b. At ? = 0.10, we do not reject H0.
c. At ? = 0.05, we do not reject H0.
d. At ? = 0.05, we accept H0.

3) The owner of a local nightclub has recently surveyed a random sample of n = 250 customers of the club. She would now like to determine whether or not the mean age of her customers is over 30. If so, she plans to alter the entertainment to appeal to an older crowd. If not, no entertainment changes will be made. If she wants to be 99% confident in her decision, what rejection region should she use?

a. Reject H0 if t < -2.34.
b. Reject H0 if t < -2.55.
c. Reject H0 if t > 2.34.
d. Reject H0 if t > 2.58.

4) A major videocassette rental chain is considering opening a new store in an area that currently does not have any such stores. A 2006 study showed that 25% of the households in the area are equipped with videocassette recorders (VCRs). It conducts a telephone poll of 300 randomly selected households in the area and finds that 96 have VCRs. The value of the test statistic in this problem is approximately equal to

a. 1.94
b. 2.80
c. 2.60
d. 1.30

5) An entrepreneur is considering the purchase of a coin-operated laundry. The present owner claims that the total population has an average daily revenue of $675 with a standard deviation of $75. A sample of 30 days reveals a daily average revenue of $625. If you were to test the null hypothesis that the daily average revenue was $675, which test would you use?

a. Z-test of a population proportion
b. Z-test of a population mean
c. t-test of population mean

6) Which of the following would be an appropriate alternative hypothesis?

a. The mean of a sample is equal to 55.
b. The mean of a sample is greater than 55.
c. The mean of a population is equal to 55.
d. The mean of a population is greater than 55.