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Both calculators run independently — change the inputs on either side to compare results.

Statistical Power Calculator

Determine the statistical power of a hypothesis test given effect size, sample size, and alpha level. Use it when designing experiments to confirm you have enough participants to detect a real effect.

Effect Size (Cohen's d)

Sample Size per Group

Alpha Level

Test Direction

Fill in the required fields to see your result.

Statistics

One-Sample T-Test Calculator

Compute the one-sample t-statistic to test whether your sample mean differs significantly from a known or hypothesised population mean. The first inferential test most students learn — used in survey analysis, quality control, and any single-group comparison against a benchmark.

Sample Mean

Population Mean (H₀)

Sample Standard Deviation

Sample Size

Fill in the required fields to see your result.

Key differences

	Statistical Power Calculator	One-Sample T-Test Calculator
Category	Statistics	Statistics
Inputs required	4	4
Result	Statistical Power	T-Statistic
What it does	Determine the statistical power of a hypothesis test given effect size, sample size, and alpha level. Use it when designing experiments to confirm you have enough participants to detect a real effect.	Compute the one-sample t-statistic to test whether your sample mean differs significantly from a known or hypothesised population mean. The first inferential test most students learn — used in survey analysis, quality control, and any single-group comparison against a benchmark.