The 
-score associated with the 
th observation of a random variable 
is given by
 |
where 
is the mean
and 
the standard
deviation of all observations 
, ..., 
.
z-Score
Explore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "z-Score." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/z-Score.html