Statistics
Recovering the original value
The same relationship inverted, for turning a target z back into a raw threshold.
The Formula
x = mean + z x SD
The same relationship inverted, for turning a target z back into a raw threshold.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| x | Raw value corresponding to that z | — | Useful for finding cutoffs such as the score needed to be two SDs above average. |
What Each Symbol Means
x
Raw value corresponding to that z
Useful for finding cutoffs such as the score needed to be two SDs above average.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate a z-score page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate A Z-Score, filed under Math. Every number the guide produces comes from substituting into this one line.