An Experiment Was Conducted to Determine the Effectiveness of a Method

Multiple Choice

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 the percentage of contamination is normally distributed,the mean percentage of contamination removed at a 98% confidence level would be _____.

A) [48.36,50.24]
B) [43.27,55.33]
C) [47.29,51.31]
D) [47.88,50.72]
E) [46.47,52.13]