1. ) A random sample of 66 seniors in NJ that averagely speaking they exercise 40 minutes per day, with a standard deviation of 10 minutes.
2. Construct a 99 percent confidence interval for the mean number of minutes they exercise?

1. Does the result in part (a) means that 99% of seniors' exercise time per day is in the range of your CI?

1. If you want to be 95% confident instead, and you want to control the maximal error of estimation to be 3 minutes, how many more seniors needs to be collected?