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Calculation Machine

T Test Calculator

One-sample and two-sample t statistics.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
t statistic
-4.40542
Mean difference
-4.1429
Standard error
0.9404
Mean 1
13.2857
Mean 2
17.4286
Approx. df
6

Quick answer

A t test measures how many standard errors separate means, telling you whether a difference is likely real.

The formula

t = (x̄ − μ) / (s/√n)

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Sample 1 values12, 14, 11, 15, 13, 16, 12
  • Sample 2 values (optional)17, 15, 19, 16, 18, 20, 17
  • Hypothesised mean (one sample)13

Result

  • t statistic-4.40542
  • Mean difference-4.1429
  • Standard error0.9404
  • Mean 113.2857
  • Mean 217.4286
  • Approx. df6

How to use the T Test Calculator

  1. 1Paste sample 1 values.
  2. 2Add sample 2 for a two-sample test, or leave blank.
  3. 3Enter the hypothesised mean for a one-sample test.

Frequently asked questions

When do I use a t test instead of z?

When the population standard deviation is unknown and the sample is small.

What t value is significant?

Roughly 2.0 for 30 observations at the 5% level — check a t table for exact df.

About this calculator