1. (45%) A random sample of 66 seniors in NJ that averagely speaking they exercise 42 minutes per day, with a standard deviation of 12 minutes.
2. Construct a 95 percent confidence interval for the mean number of minutes they exercise.
3. Does the result in part (a) means that 95% of seniors' exercise time per day is in the range of your CI?
4. If you want to be 99% confident instead, and you want to control the maximal error of estimation to be 3 minutes, how many more seniors needs to be collected?

1. (55%) A random sample of 50 female college students shows that average weight is 122 lb. with a Standard deviation of 15 lb.
2. At 5% level of significance, does the sample provide enough evidence to prove that the mean weight of all college students is more than 118lb.?
3. Also explain the meaning of alpha and P-value occurred in the content of this problem.
4. Describe what kind of error it is for type II error in the content of this problem.