In a manufacturing process,we are interested in measuring the average length of a certain type of bolt.Past data indicate that the standard deviation is .25 inches.How many bolts should be sampled in order to make us 95 percent confident that the sample mean bolt length is within .02 inches of the true mean bolt length?
A)25
B)49
C)423
D)601
E)1225

Question

Quizplus · Accepted Answer

The sample size needed to achieve a 95% confidence level with a margin of error of 0.02 inches is 601. This can be calculated using the formula: n = (Z^2 * s^2) / e^2, where Z is the z-score for the desired confidence level, s is the standard deviation, and e is the margin of error.

In a Manufacturing Process,we Are Interested in Measuring the Average