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

let's call the solutions x₁ = (5 - 2√7)/3 and x₂ = (5 + 2√7)/3

then the equation is (x-x₁)(x-x₂) = 0

if you fill that in you get a lot of numbers which you can recognize as ax²+bx+c=0.

step-by-step explanation:

you can see that a=1 (there is just an x²)

b = (-5 -2√7 + 2√7 - 5)/3 = -10/3

c = -2√7)/3 ) * (-5+2√7)/3) = -1/3

so your answer is 3x^2 – 10x – 1 = 0

$452.90 because you needed to round to the nearest cent