Question

Suppose a normally distributed set of data has a mean of 111 and a standard deviation of 15. Use the 68-95-99.7 rule to determine the percent of scores in the data set expected to be between the scores 66 and 126. Give your answer in decimal form

Answer 1

$P(66<X<126)=P(\mu-3\sigma<X<\mu+\sigma)=\frac{0.997}{2}+\frac{0.68}{2}=0.8385=83.85\%$