Statistical power calculator

Distributions: Normal, T

one varaince test tutorial


distribution left tailed distribution two tailed distribution right tailed

Power calculation

Calculate the test power basted on the sample size and draw a power analysis chart.

Use this test for one of the following tests:
One Sample Z-Test
One Sample T-Test
Two Sample Z-Test
Two Sample T-Test, Equal σ (Pooled variance)
Two Sample T-Test, Unequal σ (Welch's)

Statistic Data

digits:example digits=2: (0.001234 => 0.0012)
standard deviations:
α:significant level (0-1), maximum chance allowed rejecting H0 while H0 is correct (Type1 Error)
The power is expected to identify the effect. If one exists, H0 will be rejected. effect size (unstandardized) - the change the test is expected to identify
standardized effect size - the change divided by the standard deviation. examples:
0.2 - small effect, 0.5 - medium , 0.8 - large
σ1:standard deviation
σ2:standard deviation
n1:Group1 sample size
n2:Group2 sample size

validation message