4. The marketing director of a large department store wants to estimate the average number of customers who enter the store every ?ve minutes. She randomly selects ?ve-minute intervals and counts the...

4. The marketing director of a large department store wants to estimate the average number of customers who enter the store every ?ve minutes. She randomly selects ?ve-minute intervals and counts the number of arrivals at the store. She obtains the ?gures 48, 32, 41, 37, 56, 70, 45, 39, 32, and 78. The analyst assumes the number of arrivals is normally distributed. Using these data, the analyst computes a 95% con?dence interval to estimate the mean value for all ?ve-minute intervals.What interval values does she get?