Redo question 27, parts (a) and (b), this time assuming the population standard deviation is unknown. Use MINITAB.

Question 27

A bank manager finds from reviewing her records that the amount of money deposited on Saturday morning is normally distributed with a standard deviation of $150. A random sample of 7 customers reveals the following amounts deposited on Saturday morning:
$825 $972 $311 $1,212 $150 $1,800 $725

(a) Find a 95 % confidence interval for the mean amount of deposits by using the MINITAB program.

(b) Find a 90 % confidence interval for the mean amount of deposits by using MINITAB gain. Compare your answer to the confidence interval you computed in part (a). Which is larger?