Asurveyis being planned to determine the mean amount of time corporation executiveswatchtelevision. A pilot survey indicated that the mean time per week is 18 hours, with a standard deviation of 5.0 hours. It is desired to estimate the mean viewing time within one-quarter hour. The 95% level of confidence is to be used. (Use z Distribution Table.)

How many executives should be surveyed?(Round your z-score to 2decimal placesand round up your finalanswerto the next whole number.)