T-Test Calculator
Calculate the one-sample t-statistic to compare a sample mean against a known or hypothesized population mean.
Calculate
Enter your values below.
Result
t-statistic
0
Formula used
t = (sample mean − population mean) ÷ (sample std dev ÷ √n)
Example: sample mean 105, population mean 100, std dev 12, n=25 → t ≈ 2.08.
How to use this calculator
- Enter Sample mean, Population mean, Sample standard deviation, Sample size (n).
- Press Calculate to see your result instantly.
FAQ
Frequently asked questions
What does the t-statistic measure?
How many standard errors the sample mean is away from the population mean.
What is this test used for?
Testing whether a sample's mean is significantly different from a known or assumed population mean.
Do I need a critical t-value to interpret this?
Yes — compare this statistic to a t-distribution critical value based on your sample's degrees of freedom (n−1) and chosen significance level.
What if the t-statistic is close to zero?
It suggests the sample mean is close to the population mean, with little evidence of a real difference.