How many observations should a time study analyst plan for in an operation that has a standard

deviation of 1.5 minutes per piece if the goal is to estimate the mean time per piece to within

.4 minute with a confidence of 95.5 percent?


. How many work cycles should be timed to estimate the average cycle time to within 2 percent of

the sample mean with a confidence of 99 percent if a pilot study yielded these times (minutes):

5.2, 5.5, 5.8, 5.3, 5.5, and 5.1? The standard deviation is .253 minutes per cycle