One Sample T-Test Calculator
Test a sample mean against a known or hypothesised value.
Enter your values
Enter the sample values you are working with.
Enter the hypothesised mean μ₀ you are working with.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- t statistic
- 1.3403
- p-value (two-tailed)
- 0.2287
- Verdict
- Not significant at the 5% level
- Sample mean
- 5.1429
- Standard error
- 0.1066
- 95% CI for the mean
- 4.891 to 5.394
- Degrees of freedom
- 6
Quick answer
t = (sample mean − hypothesised mean) ÷ (s ÷ √n) with n − 1 degrees of freedom; a small p-value says the sample mean is unlikely under the null.
t = (x̄ − μ₀) ÷ (s ÷ √n)
At a glance
| What it does | Test a sample mean against a known or hypothesised value. |
|---|---|
| Category | Statistics |
| Inputs needed | Sample values, Hypothesised mean μ₀ |
| Main output | t statistic |
| Formula | t = (x̄ − μ₀) ÷ (s ÷ √n) |
| Cost | Free — no sign-up, no download |
How to use the One Sample T-Test Calculator
- 1Paste your sample values separated by commas.
- 2Enter the mean you are testing against.
- 3Read the p-value and check whether the confidence interval contains μ₀.
Inputs explained
- Sample values
- Enter the sample values you are working with.
- Hypothesised mean μ₀
- Enter the hypothesised mean μ₀ you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Sample values5.1, 4.8, 5.6, 5.2, 4.9, 5.4, 5.0
- Hypothesised mean μ₀5
Results
- t statistic1.3403
- p-value (two-tailed)0.2287
- VerdictNot significant at the 5% level
- Sample mean5.1429
- Standard error0.1066
- 95% CI for the mean4.891 to 5.394
- Degrees of freedom6
Frequently asked questions
What does the confidence interval add?
If it excludes your hypothesised mean, the two-tailed test is significant at that level — and the interval also shows the size of the difference.
Do I need normally distributed data?
For n above about 30 the test is robust. For small samples badly skewed data, use a sign test or Wilcoxon instead.
What do I need to enter into the One Sample T-Test Calculator?
Just 2 values: sample values, hypothesised mean μ₀. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the One Sample T-Test Calculator work out the answer?
t = (sample mean − hypothesised mean) ÷ (s ÷ √n) with n − 1 degrees of freedom; a small p-value says the sample mean is unlikely under the null. It applies the formula t = (x̄ − μ₀) ÷ (s ÷ √n) and shows the working so you can check each step by hand.
Is the One Sample T-Test Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.