The data below represents the number of passengers per flight for a random sample of 50 flights from Halifax to Toronto on a particular airline.

a. Estimate the average number of passengers per flight with a 95% confidence level.

b. The company would like to estimate the population mean number of passengers per flight to within 5 passengers with 95% confidence. How large a sample is needed?

Number of passengers 163 152 165 138 94 147 137 119 123 166 95 170 96 117 129 125 148 180 152 149 167 120 120 159 150 119 113 147 169 151 116 150 110 110 143 90 34 145 156 165 174 133 128 100 86 148 139 150 145 100