0
$\begingroup$

In a given population, a score of X= 88 corresponds to z= +2.00 and a score of X= 79 corresponds to z= -1.00. Find the mean and standard deviation for the population.

I know how to find X and z-scores as well as how to plug things into the z-score formula, but I'm not sure how to solve this one. It says to sketch out a distribution table and find where the mean and SD fall on it, but I'm not sure how to do that.

$\endgroup$

1 Answer 1

2
$\begingroup$

A z score is just a way of saying that it's that many standard deviations above or below the mean. Since they've given you two values and the z scores you can figure it out. Let $m,s$ denote the mean and standard deviation of the distribution. Then,

$$X_1-X_2=9=z_1-z_2=3s$$

So the $s=3$ and $m=X_1 - 2s = 82$.

$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .