HW 8.1

#1 The mean exam score for 43 male high school students is 20.5 and the population standard deviation is 4.8. The mean exam score for 53 female high school students is 20.1 and the population standard deviation is 4.6. At =0.01, can you reject the claim that male and female high school students have equal exam scores?

(a) Find the critical value(s)

(b)identify the rejection region(s).

(c) Find the standardized test statistic z.

(d)Decide whether to reject or fail to reject the null hypothesis and interpret the decision in the context of the original claim.

#2 A real estate agency says that the mean home sales price in City A is the same as in City B. The mean home sales price for 30 homes in City A is $127,436. Assume the population standard deviation is $25,873. The mean home sales price for 30 homes in City B is $112,267. Assume the population standard deviation is $27,110. At =0.01, is there enough evidence to reject the agency's claim?

(a) Find the critical value(s)

(b)identify the rejection region(s).

(c) Find the standardized test statistic z.

(d)Decide whether to reject or fail to reject the null hypothesis and interpret the decision in the context of the original claim.

#3 A sociologist claims that children spent more time watching television in 1981 than children do today. A study was conducted in 1981 to find the time that children watched television on weekdays. Recently, a similar study was conducted. The results of these studies (in hours per weekday) are shown below. Assume the population standard deviation is 0.7 for 1981 and 0.8 for today. At =0.05, can you support the sociologist's claim?

1981 Recently 1.8 1.3 3.1 0.9 1.2 1.7 1.9 1.1 2.6 1.7 1.8 1.8 1.6 1.6 1.5 2.9 3.4 2.7 2.8 1.1 2.1 3.2 1.7 2.9 2.4 1.5 3.4 3.3 1.4 2.1 3.2 2.1 1.6 2.4 2.5 1.1 1.4 2.8 1.8 0.8 3.3 1.2 1.6 3.1 1.5 2.6 1.5 1.6 1.6 3.2 1.8 2.9 1.2 2.1 1.7 1.9 1.6 2.7 1.6 3.3

Identify H0 and Ha.

(a) Find the critical value(s)

(b)identify the rejection region(s).

(c) Find the standardized test statistic z.

(d)Decide whether to reject or fail to reject the null hypothesis and interpret the decision in the context of the original claim.