Find the sample size.
-A manufacturer of cheese filled ravioli wants to make sure that its automatic filling
Process is on target. Based on a sample of 25 ravioli the mean weight of cheese filling is
Estimated to be 15 grams with a standard deviation of 1.5 grams. However, the quality
Control inspectors wish to estimate the mean weight of cheese filling more accurately so
That they can be 99% confident that it is within .25 grams of the true mean. How many
Ravioli should they sample?
A) 150
B) 543
C) 212
D) 410
E) 239

Question

Quizplus · Accepted Answer

To find the sample size, use the formula for sample size in estimating a mean: n = (Z*σ/E)^2. For 99% confidence, Z is approximately 2.576. Given σ = 1.5 and E = 0.25, n = (2.576*1.5/0.25)^2 = 238.37, which rounds up to 239.

Find the Sample Size