Question

1)Will listening to different forms of music affect average grades on exam? Two different groups were studied - Rap and Mozart - with the following results: those who listened to Rap music while studying had z = 86.7, with Sx = 3.9 and n = 29 while those who listened to Mozart while studying had i = 85.6 with Sg = 3.2 and n = 20. Using this data, construct a 99% confidence interval for the difference between average grades for the two different groups. Based on this interval, do we have evidence that those who listen to Rap will have a higher average than those who listen to Mozart? Why?

2)An exit poll is taken on election night where 532 out of 1026 of those surveyed said they voted for a particular candidate. Construct a 99% confidence interval for proportion of voters who will choose this candidate. Using this interval, can you predict a winner in this race? Give a statistical basis for your response.

3) Past studies have shown that the average recovery time from knee replacement is 180 days. Clinical trials were performed using new physical therapy methods in an effort to lower the recovery time. Here are the results from those trials: n = 45, x = 177.6 and Sy=4.1. Based on the results of these trials, do we have evidence that this new therapy will lower the average recovery time from knee replacement? Be sure to state the null an alternate hypotheses.

Answer 1