The operations manager of a large production plant would lik

The operations manager of a large production plant would like to estimate the average amount of time workers take to assemble a new electronic component. After observing a number of workers assembling similar devices, she guesses that the standard deviation is 10 minutes. How large a sample of workers should she take if she wishes to estimate the mean assembly time to within 16 seconds with confidence level 98%.

Solution

STd dev - 8 minutes=480 seconds

n = sample size =?

Confidence level =95%

Margin of error <= 21 seconds

z alpha/2 for 95% = 1.96

Margin of error = 1.96(std dev/ rtn) <= 21 seconds

i.e. 1.96(480)/21 <= rtn

n>=2007.4

Or n should be atleast 2008.