Question

Managers at an automobile manufacturing plant would like to estimate the mean completion time of an assembly line operation, μ. The managers plan to choose a random sample of completion times and estimate μ via the sample. Assuming that the standard deviation of the population of completion times is 10.1 minutes, what is the minimum sample size needed for the managers to be 95% confident that their estimate is within 1.7 minutes of μ? Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements).

Answer 1

We have given here,                  
                  
Population standard deviation =   10.1 minutes  
Margin of error =E=1.7   minutes
Level of significance =   1-0.95=0.05  
Z critical value is (by using Z table)=1.96