23. (4 points) A survey of 601 women for the American Orthopedic Foot and Ankle Society revealed that 200 wear flats to work.

a) Calculate a 99% confidence interval to estimate the percentage of all women who wear flats to work.

b) Interpret your interval from (a).

c) What is the margin of error for your interval?

24. (10 points) According to the American Time Use Survey, the typical American spends 154.8 minutes (2.58 hours) per day watching television. Do people without cable TV spend less time each day watching television? A survey of 31 people without cable TV results in a mean time watching television per day of 128.7 minutes, with a standard deviation of 46.5 minutes. Conduct the appropriate test, using the rejection region method, to determine if people without cable TV spend less time watching television at a 0.05 level of significance.

a) State the null and alternative hypotheses you would use to test this claim.

b) State the test you will use.

c) Sketch your rejection region and label the cutoff(s), or show the inequality you use to make your decision.

d) Calculate your test statistic.

e) State your decision (reject H0 or fail to reject H0).

f) Interpret your decision in terms of the original problem/situation.

25. (10 points)In a survey of 1000 US Adults, 605 say it is somewhat or very likely that life exists on other planets. A researcher claims that more than 60% of adults believe it is somewhat or very likely that life exists on other planets. At alpha = 0.05, can you support the researcher's claim? Use the p-value method.

a) State the null and alternative hypotheses you would use to test this claim.

b) State the test you will use.

c) Calculate your p-value.

d) State your decision (reject H0 or fail to reject H0).

e) Interpret your decision in terms of the original problem/situation.

26. (10 points) In one area, monthly incomes of college graduates have a standard deviation of $450. It is believed that the standard deviation of monthly incomes of non-college graduates is higher. A sample of 21 non-college graduates are randomly selected and found to have a standard deviation of $550. Does the evidence suggest that the monthly incomes of non-college graduates have a higher standard deviation? Use = 0.05. Use the rejection region method.

a) State the null and alternative hypotheses you would use to test this claim.

b) State the test you will use.

c) Sketch your rejection region and label the cutoff(s), or show the inequality you use to make your decision.

d) Calculate your test statistic.

e) State your decision (reject H0 or fail to reject H0).

f) Interpret your decision in terms of the original problem/situation.