Confidence intervals of a population mean1.now suppose you do not know the population mean fee charged to h& r block customers last year. instead, suppose you take a sample of size n=40 and find a sample mean of 175. assume that the distribution for fees is normally distributed with a population standard deviation of $50.a. calculate the standard error of x (line over x)b.95% confidence interval for the population mean of fees at h& r block. i.calculate the margin of error (moe) of using a 5% significance level. ii. calculate the 95% confidence interval. iii. write one complete sentence about the interpretation of the confidence interval. a.90% confidence interval for the population mean of fees h& r block. i.calculate the margin of error (moe) of using a 10% significance level. ii. calculate the 90% confidence interval. iii. suppose an analyst belief that the population mean fee is equal to $185. using a 90% confidence level. can we conclude the analyst is right? why or why not? show every step!