P-value · standard normal z test
P-value · standard normal z test: use z test statistic, alternative hypothesis. Review the formula, worked example and calculation steps.
Inputs
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Formula & explanation
Two-sided p = 2Φ(−|z|); right p = 1−Φ(z); left p = Φ(z)
Variables & units
- Z test statistic
- Numeric value · minimum -12, maximum 12
- Alternative hypothesis
- Select an option
Worked example
z=1.96 gives a two-sided p-value of approximately 0.049996.
Assumptions
Normal z tests only; not Student t, chi-square, F or exact tests. Tail approximation can have absolute error around 10⁻⁷; very small p-values may display as zero.
References
Formula version 1.0.0. JavaScript floating-point arithmetic applies. Results display up to 6 decimal places; stored values retain available precision. Use the units shown.
Practice with an example
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