*z* score Calculator

This calculator is from
http://www.fourmilab.ch/rpkp/experiments/analysis/zCalc.html, with thanks
going to John Walker.
Note that there is no closed form solution to come up with exact z-score
cumulative probability values. Therefore, the cumulative probability calculated from the *z-score*
is an approximation. The calculators below calculate to six decimal places of
accuracy, which is more than adequate for most purposes.

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## Calculate cumulative probability *p* from *z*

One of the most common probability calculations is determining, given
the measured *z* value from an experiment or set of
experiments, the cumulative probability. Enter
the *z* value in the box below, press the **Return** key or
the **Calculate** button, and the probability will appear in the Q
box.

## Calculate *z* from cumulative probability *p*

To determine the *z* score indicating a cumulative probability *p*,
enter *p* in the box below and
press the **Return** key or the **Calculate** button.

close calculator