1.(45%) A random sample of 53 college students shows that average weight is 140 lbs with a Standard deviation of 26 lb.

(a)Construct a 90 percent confidence interval for the mean weight of all college students.

(b)Does the result in part (a) means that 90% of students' weight is in the range of your CI?

(c)If you want to be 99% confident instead, and you want to control the maximal error of estimation to be 4 lbs, how many more college students need to be collected?