Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

Exercise 9

Provide the following information
(a) What is the level of significance State the null and alternate hypotheses.
(b) Check Requirements What sampling distribution will you use Explain the rationale for your choice of sampling distribution. Compute the value of the sample test statistic.
(c) Find (or estimate) the P -value. Sketch the sampling distribution and show the area corresponding to the P -value.
(d) Based on you answers in part (a) to (c), will you reject or fail to reject the null hypothesis Are the data statistically significant at level
(e) Interpret your conclusion in the context of the application.
Note: For degree of freedom d.f. not given in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P -value by a small amount and therefore produce a slightly more "conservative" answer.
Longevity: Honolulu USA Today reported that the state with the longest mean life span is Hawaii, where the population mean life span is 77 years. A random sample of 20 obituary notices in the Honolulu Advertizer gave the following information about life span (in years) of Honolulu residents:
72 68 81 93 56 19 78 94 83 84
77 69 85 97 75 71 86 47 66 27
i. Use a calculator with mean and standard deviation keys to verify that
= 71.4 years and s 20.65 years.
ii. Assuming that life span in Honolulu is approximately normally distributed, does this information indicate that the population mean life span for Honolulu residents is less than 77 years Us a 5% level of significance.