1. (45%) A random sample of 53 college students shows that average weight is 140 lbs with a Standard deviation of 26 lb.
2. Construct a 90 percent confidence interval for the mean weight of all college students.
3. Does the result in part (a) means that 90% of students' weight 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 4 lbs, how many more college students need to be collected?

1. (550%) A random sample of 60 college students shows that average weight is 170 lb. with a Standard deviation of 21 lb.
2. At 1% level of significance, does the sample provide enough evidence to proof that the mean weight of all college students is more than 165 lb.?
3. Also explain the meaning of alpha and P-value occurred in this problem.
4. Describe what kind of error it is for type I error in the content of this problem.