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Two-Sample t-TestStatLens

Choose a dataset:

Edit or paste two columns (CSV with headers, group and value):

Open a CSV, TSV, or JSON file:

Group 1 Group label: Mean (x₁): SD (s₁): n₁:

Group 2 Group label: Mean (x₂): SD (s₂): n₂:

Results update as you type — no need to press anything.

Grouping variable: Response variable:

Parameters

H₀: μ₁ − μ₂ = 0 =

H_a: μ₁ − μ₂ 0 0

Select a dataset or enter summary statistics — results appear automatically.

Just estimating? Confidence Interval for a Difference in Means →

Two-Sample t-Test

Compare the means of two independent groups (μ₁ − μ₂), using a t-statistic and the t-distribution.

Load data from the Datasets, Edit Data (a group column and a value column), or Open File/URL tab, or use Enter Summary to type the mean, SD, and n for each group.
Grouping / response selectors let you choose the columns when raw data has more than one. Swap Group 1 ↔ Group 2 flips which group is subtracted.
Alternative (H_a): click the toggle to cycle ≠, <, > for a two-sided or one-sided test.
Null value: standard mode tests μ₁ − μ₂ = 0. Turn on Expert mode (settings gear) to make the null difference δ₀ editable and test a nonzero difference.
Conditions checkpoint reminds you to check sample sizes and shape before trusting the result.
Results — t, df, p-value, the confidence interval, and the plot — appear automatically as you change inputs. There is no Compute button.

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