t-Test Sample Size Calculator

Standard Deviation:

Difference to Detect:


Confidence:
90% 95% 99%

Power:
50% 60% 75% 90% 95% 99%

Test Type:
Compare a Mean to a Standard Compare Two Means

Please enter the number of standard deviation and the difference to detect.

This calculator tells you the estimated number of replicates required to perform a t-Test with the specified confidence and power.

The standard deviation comes from previous data. If you don't know this, you will need to run a few replicates (3 to 5) to determine an estimate.

The difference to detect comes from your engineering judgement.

The sample size is for each mean.

You can receive the Sample Size Calculator, a small program that calculates sample size for Confidence limits, t-Tests, Cpk and Percentages, the minimum number of trials for a designed experiment, and sample size with maximum allowable rejects for reliability studies. It also includes help files for everything. Make a donation of $20 or more to St Jude Children's Research Hospital and receive the Sample Size Calculator for free.
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