Analyze the given situation and determine the required solution.

In no. 3 determine the grade of the student in Statistics if the grade in General Mathematics is:

a. 75

b. 80

c. 85

d. 90

You take a sample of 25 from the population of test scores in the long test in Math, and you obtained a mean of 60.

(a) You know in advance that the population standard deviation is 10. What is the 99% confidence interval on the population mean?

(b) Suppose the population standard deviation is unknown you obtained sample standard deviation of 10. What is the 99% confidence interval in the mean now?