For a random sample of 36 Alameda County kindergarten classes, the average class size was 25 with a standard deviation of two. a. Calculate and report a 99% confidence interval for the mean...

Don't understand can you pleas show work and formula used. Thank you.

Extracted text: For a random sample of 36 Alameda County kindergarten classes, the average class size was 25 with a standard deviation of two. a. Calculate and report a 99% confidence interval for the mean kindergarten class size in Alameda County. b. Terry Teacher suspects that kindergarten class sizes in Alameda county are larger than average. According to the California Department of Education, the average kindergarten class size in California is 21.9. Given the confidence interval you calculated in part (a), is Terry's suspicion is accurate? Explain why or why not.