A sample of the diameters of plumbing pipes approximate a sy

A sample of the diameters of plumbing pipes approximate a symmetrical, bell-shaped distribution. The arithmetic mean is 10.0 inches, and the standard deviation is 0.10 inches. Based on the Empirical rule, what percent of the observations will lie between 9.80 inches and 10.30 inches? 97.4% 83.9% 95.0% 68.0%

Solution

mean=10

sd=0.1

95% of values fall between mean-2*sd, mean +2*sd

so answer is 95%.