One-sample t-test
Find sample size:
If you can estimate group mean and standard deviation, use this form to find the number of subjects you need.
Group mean:
Comparison value:
Standard deviation:
Click here for sample size:
You will need subjects
Find effect size:
If you know the number of subjects and the standard deviation of your measurement, use this form to see what mean values will be significant.
Number of subjects:
Standard deviation:
Comparison value:

Click here for effect size:
You can show significance with a mean >
or a mean <
For different power or significance level, change the fields below:
Alpha: Prob(reject H0 when H0 is true)
Power: Prob(reject H0 when H1 is true)
Choose another study design
v. 03/03
Source: G.W. Snedecor & W.G. Cochran
Statistical Methods (7th ed., p. 104)