Suppose we wish to estimate the average number of hours per week that Americans watch TV. Use the following data from an SRS to find a 90% confidence interval: 30        64        49        40        21        58        9          43        39            43

Suppose that a health expert has claimed that 28% of college students smoke cigarettes. To investigate this claim, researchers survey a random sample of college students. Using this sample, a 95% confidence interval for the percentage of college students who smoke is found to be 19% to 24%. On the basis of this interval, explain whether the claim that 28% of all college students smoke is reasonable or not. You may need to use the appropriate table in the Appendix of Tables to answer this question. a) The claim of 28% is reasonable because the value 28% is not in the confidence interval. b) The claim of 28% is not reasonable because the value 28% is in the confidence interval.     c) The claim of 28% is not reasonable because the value 28% is not in the confidence interval. d) The claim of 28% is reasonable because the value 28% is in the confidence interval.

A learn-to-type software program claims that it can improve your typing skills. To test the claim and possibly help yourself out, you and five of your friends decide to try the program and see what happens. Use the table below to construct a 99% confidence interval for the true mean change in the typing speeds for people who have completed the typing program. Let Population 1 be the typing speed before taking the program and Population 2 be the typing speed after taking the program. Round the endpoints of the interval to one decimal place, if necessary. Typing Speeds (in Words per Minute) Before After 52 47 44 42 40 46 50 43 46 34 38 50 Lower end point upper end point

In a random sample of 145 students, we find that 53% have attended a baseball game at some point in their college careers. Construct a 95% confidence interval with a confidence interval of .53.