Rearrange this expression into quadratic form, 2++=0 , and identify the values of , , and . 0.20=225−

Explanation:

The raw score is x = 64, and we want to find its corresponding z score.

The mean and standard deviation are mu = 48 and sigma = 8 respectively.

The z score is...

z = (x-mu)/sigma

z = (64-48)/8

z = 16/8

z = 2

A z score of 2 means we're 2 standard deviations above the mean.

As the formula above implies, we find the difference from the raw score (x) to the mean (mu). Then we divide over sigma to find out how many sigma steps we have to take to go from mu to x.

A negative z score would indicate the raw score is below the mean.