An experiment was conducted to determine the effectiveness of a method designed to remove oil wastes found in soil.Three contaminated soil samples were treated.After 95 days,the percentage of contamination removed from each soil sample was measured with a mean of 49.3% and a standard deviation of 1.5%.If we wished to narrow the boundary around $\mu$ for a 98% confidence interval to within 0.5%,how many soil samples should be in our experiment.
A)437
B)33
C)9
D)6
E)3

Question

Quizplus · Accepted Answer

To narrow the confidence interval to within 0.5% with a 98% confidence level, we use the formula for the sample size: n = (Z*σ/E)^2, where Z is the Z-score for 98% confidence, σ is the standard deviation, and E is the margin of error (0.5%). Using Z ≈ 2.33 for 98% confidence, σ = 1.5, and E = 0.5, we calculate n ≈ 437.

An Experiment Was Conducted to Determine the Effectiveness of a Method