Calculus (percent symbol)

Question

The number of potholes in any given 1 mile stretch of freeway pavement in Pennsylvania has a bell-shaped distribution. This distribution has a mean of 65 and a standard deviation of 7. Using the empirical rule, what is the approximate percentage of 1-mile long roadways with potholes numbering between 51 and 72?

Answer 1

This is statistics. 51 is 2 standard deviations below the mean of 65, and 71 is 1 standard deviation above the mean. The empirical rule for a bell curve tells us that the percentage of roads that will fall between these points is 13.5 + 34 + 34 or 81.5