I need help with all of those

Asimple random sample of size nequals14 is drawn from a population that is normally distributed. the sample mean is found to be x overbar equals 70 and the sample standard deviation is found to be sequals13. construct a 90% confidence interval about the population mean

1: 4 if the wew 35 surfboards at the beach how many were short boards?

Which of the following is missing in the explicit formula for the compound interest geometric sequence below?