1. A sample of 33 observations is selected from a normal population. The sample mean is 30, and the population standard deviation is 4. Conduct the following test of hypothesis using the 0.05 significance level.
2. At the time she was hired as a server at the Grumney Family Restaurant, Beth Brigden was told, “You can average $73 a day in tips.” Assume the population of daily tips is normally distributed with a standard deviation of $4.38. Over the first 35 days she was employed at the restaurant, the mean daily amount of her tips was $74.23. At the 0.01 significance level, can Ms. Brigden conclude that her daily tips average more than $73?
3. The Rocky Mountain district sales manager of Rath Publishing Inc., a college textbook publishing company, claims that the sales representatives make an average of 40 sales calls per week on professors. Several reps say that this estimate is too low. To investigate, a random sample of 38 sales representatives reveals that the mean number of calls made last week was 41. The standard deviation of the sample is 2.6 calls. Using the 0.025 significance level, can we conclude that the mean number of calls per salesperson per week is more than 40?
4. A United Nations report shows the mean family income for Mexican migrants to the United States is $26,700 per year. A FLOC (Farm Labor Organizing Committee) evaluation of 21 Mexican family units reveals a mean to be $28,450 with a sample standard deviation of $10,850. Does this information disagree with the United Nations report? Apply the 0.01 significance level
5. The following information is available.
H0 : μ ≥ 220
H1 : μ < 220
A sample of 64 observations is selected from a normal population. The sample mean is 215, and the population standard deviation is 15. Conduct the following test of hypothesis using the .025 significance level.
6. Given the following hypotheses:
H0 : μ ≤ 10
H1 : μ > 10
A random sample of 10 observations is selected from a normal population. The sample mean was 12 and the sample standard deviation 3. Using the .05 significance level
7. Given the following hypotheses:
H0 : μ = 400
H1 : μ ≠ 400
A random sample of 12 observations is selected from a normal population. The sample mean was 407 and the sample standard deviation 6. Using the .01 significance level: