Question

A bank manager wants to determine the percent of time that tellers are working and idle. She decides to use work sampling, and her initial estimate is that the tellers are idle 15% percent of the time. How many observations should the manager take in order to be 95.45 percent confident that the results will not be more than 4% percent away from the true result?

Answer 1

Number of observation = 3.187

Explanation:

Given data:

Total percent of time during which teller sit idle 15%

confident interval is given as 95.45%

percent of accuracy 4%

Number of observation taken by manager to be sure about 95.45% is calculated as
`Number of observation = (idle\ time\ percent  * ( 1 -idle\ time\ percent ))/(percent\ of\ accuracy)`

Putting all value to get observation value
`Number\ of\  observation = (0.15 * (1 - 0.15))/(0.04)`

Number of observation = 3.187