explain please

Soru 1 Cevap kaydedildi 30,00 uzerinden isaretlenmis Soruyu isaretle University of X wants to learn how much students pay for their textbooks during the spring semester. From a random sample of 49 students from University of X was chosen. The mean cost was found to be 750TL, and the sample standard deviation was 56. Assuming that the population is normally distributed, a) Find the margin of error of a %95 confidence interval for the population mean. b) Find a %95 confidence interval for the population mean. c) How many students should be sampled so that the sampling error is at most 5? *Please explain the solution steps briefly (which statistical distribution, why?..) *When you need to use the notation of population mean, you can write "mu", similarly "xbar", "sigma", "variance"