William is a waiter at Seventh Heaven Hamburgers. He wants to estimate the mean amount each group at a table leaves for a tip. A random sample of 36 tables has mean x with bar on top space equals space $ 9.30. Assume σ is known to be $3.88. Answer the following questions to create a 90% confidence interval for µ, the mean amount of all group tips. A. Find the critical value (just enter the number):

B. Compute the maximal margin of error. Do not use the dollar symbol ($). Just enter the number, rounded to two decimal places:

C. Give the 90% confidence interval. Use bracket symbols like we did in class. Do not use dollar symbols ($). Write the smaller number first, the larger number second, separated by a comma: