Use the empirical rule. the mean speed of a sample of vehicles along a stretch of highway is 66 miles per hour, with a standard deviation of 4 miles per hour. estimate the percent of vehicles whose speeds are between 62 miles per hour and 70 miles per hour. (assume the data set has a bell-shaped distribution.) 99.7

The percentage of that vehicles whose speeds are between 62 miles per hour and 70 miles per hour

P(62≤X≤70) = 68.76

Step-by-step explanation:

Step(i):-

Given that the mean of the Population = 66miles per hour

Given that the standard deviation of the Population = 4 miles per hour

Let 'X' be the random variable in normal distribution

Let x= 62

let x=70

Step(ii):-

The probability that vehicles whose speeds are between 62 miles per hour and 70 miles per hour

P(62≤X≤70) = P(-1≤Z≤1)

                  = P(z≤1) -P(Z≤-1)

                 = P(Z≤1)+P(Z≤1)

                 = 2×P(Z≤1)

                 = 2×0.3438

                 = 0.6876

The percentage of that vehicles whose speeds are between 62 miles per hour and 70 miles per hour

P(62≤X≤70) = 68.76