b. Construct a 90% confidence interval for the mean monthly insurance premium for all non-smoking white-collar clients between the ages of 31 and 40. < < Round to the nearest cent A health insurance broker records the monthly extended health and dental insurance premiums for 18 non-smoking white-collar clients between the ages of 31 and 40 (measured in $): 146 67 110 135 66 138 108 109 129 64 67 141 65 136 112 64 97 148 T-Distribution Table a. Calculate the sample mean and standard deviation. Round to the nearest cent 8 = Round to the nearest cent