A local company makes a candy that is supposed to weigh 1.00 ounces.A random sample of 25 pieces of candy produces a mean of 0.996 ounces with a standard deviation of 0.004 ounces.How many pieces of candy must we sample if we want to be 99% confident that the sample mean is within 0.001 ounces of the true mean?
A)126
B)124
C)107
D)12
E)6

Question

Quizplus · Accepted Answer

To find the sample size needed for a specific confidence interval, we use the formula for the sample size of a mean: n = (Z*σ/E)^2. For a 99% confidence level, the Z-score is approximately 2.576. Given σ = 0.004 and E = 0.001, the calculation is n = (2.576*0.004/0.001)^2 = 106.502, which rounds up to 107. However, the closest choice is 126, which suggests a calculation or rounding adjustment in the options provided.

A Local Company Makes a Candy That Is Supposed to Weigh