A quality engineer in a light bulb factory is planning a study to estimate the average life of a large shipment of light bulbs.The engineer wants to estimate the average life within plus or minus 15 hours with 95 percent confidence.Assuming a process standard deviation of 100 hours,determine the sample size for this study.
A)7
B)43
C)58
D)171

Question

Quizplus · Accepted Answer

The formula to calculate the sample size is:

n = (Z^2 * σ^2) / E^2

Where:
Z = 1.96 (for 95% confidence level)
σ = 100 (process standard deviation)
E = 15 (desired margin of error)

Plugging in the values, we get:

n = (1.96^2 * 100^2) / 15^2
n = 170.944

Rounding up to the nearest integer, the sample size required is 171. Therefore, the best choice is D.

A Quality Engineer in a Light Bulb Factory Is Planning