A survey is being planned to determine the mean amount of time corporation executives watch television. A pilot survey indicated that the mean time per week is 14 hours, with a standard deviation of 2.0 hours. It is desired to estimate the mean viewing time within 30 minutes. The 98% level of confidence is to be used.

Question

A survey is being planned to determine the mean amount of time corporation executives watch television. A pilot survey indicated that the mean time per week is 14 hours, with a standard deviation of 2.0 hours. It is desired to estimate the mean viewing time within 30 minutes. The 98% level of confidence is to be used.
  
How many executives should be surveyed? (Round your z-score to 2 decimal places and round your final answer to the next whole number.)
  
  Number of executives

Steve · Answer

play around with Z table stuff here: http://davidmlane.com/hyperstat/z_table.html