ZScores
A zscore, sometimes called a standardized score, is
simply the number of standard deviations an observation is
from the mean. It is found by subtracting the mean and then
dividing by the standard deviation, or:
z=(xµ)/σ
The equation has four variables. If you know any three,
you can solve for the fourth.
Finding zscores is an essential step in using the Normal
probability distribution if people use tables rather than
having a computer do the computation. (If you have data that
is normally distributed (a topic of an upcoming section),
converting to zscores gives transformed numbers with a mean
of zero and a standard deviation of one.)
