# Student Needing Help

#### seabass069

##### New Member

A normal population has a mean of 20.0 and a standard deviation of 4.0.

Compute the z-value associated with 25.

#### JohnM

##### TS Contributor
The z value or z score represents how many standard deviations a particular score is from its average or mean:

z = (x - mu)/s

x = the value at which we need a z score
mu = the average or mean
s = standard deviation