The head of maintenance at XYZ Rent-A-Car believes that the mean number of miles between services is 3408 miles, with a variance of 249,001. If he is correct, what is the probability that the mean of a sample of 36 cars would be less than 3245 miles

The probability that the mean of a sample of 36 cars would be less than 3245 miles

P(X⁻≤3245) = 0.975

Step-by-step explanation:

Step(i):-

The mean number of miles between services

                   μ= 3408 miles  

The Variance of miles between services

                σ² = 249,001

                σ = √249,001 = 499

Let 'X' be a random variable in a normal distribution

Given sample size 'n' =36

Step(ii):-

          Z = -163/83.16 = 1.96

The probability that the mean of a sample of 36 cars would be less than 3245 miles

P(X⁻≤3245)  =   P(Z≤1.96)

                   =   0.5 + A(1.96)

                   =  0.5 + 0.4750

                  =   0.975

Final answer:-

The probability that the mean of a sample of 36 cars would be less than 3245 miles

P(X⁻≤3245) =0.975

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.

slope is 35 and 20 miles is the y-intercept.

step-by-step explanation: