Critical Value Calculator

Calculates the critical value for the following distributions:
t critical value calculator, z critical value calculator, f critical value calculator, chi square critical value calculator.

What is the critical value?

The critical value the boundary between the accepted region (green) and the rejected region (red). Under the assumption that the H0 is correct, the probability to get the critical value or more extreme value (red) is the significance level (α).
What is more extreme?
Two-tailed: smaller than the small value or larger than the large value.
Left-tailed: smaller than the small value.
Right-tailed: larger than the large value.

Z critical value calculator

To calculate the critical value for the z statistic, choose the normal distribution and enter the mean and standard deviation.
For a standard normal distribution enter μ = 0 and &sigma = 1.

T critical value calculator

To calculate the critical value for the t statistic, choose the T distribution and enter the degrees of freedom (n - 1).

F critical value calculator

To calculate the critical value for the F statistic, choose the F distribution and enter the degrees of freedom (n - 1).

Chi square critical value calculator

To calculate the critical value for the Chi-square statistic, choose the Chi-square distribution and enter and enter the degrees of freedom.

Standard deviation

The statistic's standard deviation. For example, for the average test, you should enter σ/√n.