Calculator
Enter the values below. Every quantity identifies its unit or meaning.
units
units
observations
units
units
observations
%
Formula / method
z = (x̄₁−x̄₂)/√(s₁²/n₁+s₂²/n₂). Normal reference approximation.
z = (x̄₁−x̄₂)/√(s₁²/n₁+s₂²/n₂). Normal reference approximation.
How to use this calculator
What to enter
Enter or select the following as requested: Mean 1; SD 1; n 1; Mean 2; SD 2; n 2; Significance level (α). Follow the units, valid ranges, examples, and options displayed beside each field.
What the result means
The statistic summarizes the entered data using the measure named by the calculator. Results depend on the supplied observations and, where applicable, whether the data are treated as a sample or an entire population.
When to use it
Use this to summarize or compare a dataset. Check data quality, missing values, units, and the sample-versus-population convention before interpreting the statistic.