need help with question 32

Suppose that a simple random sample is taken from a normal population having a standard deviation of 9 for the purpose of obtaining a 90% confidence interval for the mean of the population. Complete parts (a) through (c) below. a. It the sample size Is 4, obtain the margin of error. . . . . . The margin of error for a sample size of 4 is (Round to two decimal places as needed.) b. Repeat part (a) for a sample size of 36. The margin of error for a sample size of 36 is (Round to two decimal places as needed.) c. Can you guess the margin of error for a sample size of 324? Explain your reasoning. The marain of error for a sample size of 324 is