In a population distribution, a score of x=57 corresponds to z=-0.25 and a score of x=87 corresponds to z=1.25. find the mean and standard deviation for the population.

Here is dependence between scores and x-values:

where is the mean, is standard deviation and i changes from 1 to 2.

1. When i=1, then

2. When i=2, then

Now solve the system of equations:

Subtract first equation from the second:

Then

the mean is 62, the standard deviation is 20.

The mean is 62 and the standard deviation is 20 for the population.

Step-by-step explanation:

Let be the mean and be the standard deviation .

Formula to calculate z-score corresponds to random variable x on normal curve.

Given : In a population distribution, a score of x=57 corresponds to z=-0.25 and a score of x=87 corresponds to z=1.25.

Eliminate equation(1) from equation(2), we get

Put value of in (1)

Hence, the mean is 62 and the standard deviation is 20 for the population.

.19875994384

step-by-step explanation:

1699/ 8548

no he doesnt because "-16' is negatiive

step-by-step explanation: