Skip to Main Content

MASH : Maths and Stats Help

Paired Samples t-Test


A Paired-Samples t-Test compares the means between two related groups, such as comparing the difference between pre-intervention and post-intervention test results.

It is considered a parametric test and is only suitable for parametric data. To check if your data is parametric, please check out the dedicated guide: Parametric or Not Guide (PDF) 

If your data is non-parametric you should consider using a Wilcoxon Test.


Test Procedure

  1. Click Analyze > Compare Means > Paired-Samples T Test

  2. Within the Paired Samples t-Test box, select the two variables you wish to analyse and move to them to the Paired Variables Box using the right arrow

  3. Click OK



SPSS will generate three tables, for this test we need two, the Paired Samples Statistics and the Paired Samples Test.


Paired Samples Statistics

This table shows a selection of descriptive statistics: the sample size (N), the mean of score (Mean), and the standard deviations (Std. Deviation), these are the three descriptives that are typically reported.

Paired Samples Test

This table shows the specific test results including the t-statistic (t), the degrees of freedom (df) the two-tailed significance or p-value (Two-Sided p), the mean difference between the groups (which we report below using ), and the 95% Confidence Interval (95% Confidence Interval of the Difference).

Reporting the Results in APA Formatting

Students’ test results were compared before and after the intervention. On average, students performed better after the intervention (M = 73.30, SD = 11.91) than before (= 69.00, SD = 6.64). A Paired-Samples t-Test indicated this difference, d̄ = 4.30, 95%CI [0.83, 7.77] was statistically significant, (19) = 2.60, = .018.