Ties: what it means and how to read it

In the report: Ties — Pairs where the two values are equal; they are left out of the test.

How to read it

Only the rows that changed count, so many ties make the test weaker.

In plain words

A teacher gave 30 students a test before a course and after it. Some students got exactly the same score both times, and she wanted to know how many students the test really looks at. She counted Ties and got 5. Those 5 students did not change, so the test leaves them out. Now she knows that only 25 of the 30 students count. If 20 of the 30 had been ties, the test would have only 10 students to work with, and she would not trust its answer much.

Example

The cell with Ties is selected in each report; point at a label to see its note.

— the sample data (50 rows) the examples use
— two-sided =STATS_WILCOXON(Data!A1:T51, "before,after")

Where you see it

STATS_WILCOXON — Wilcoxon signed-rank test for two related measurements of the same rows (before / after) — the rank replacement for STATS_PAIRED when the differences are not normal.

Test variant — student — the classic test, which assumes equal variances in the groups; welch — Welch's test, which does not.
Variance ratio — The largest group variance divided by the smallest. 1 — the variances are equal.
Group size ratio — The size of the largest group divided by the size of the smallest. 1 — all groups have the same number of values.
Test of equal variances — Tests whether the groups have the same variance. By default it is based on the median — the Brown–Forsythe modification of Levene's test, robust to skewed data; "based on mean" is the original Levene test, the one SPSS T-TEST and ONEWAY print by default — set homogeneity to "levene" to match SPSS.
Posthoc comparisons — Posthoc (pairwise) comparisons: every pair of groups compared after the ANOVA, with p corrected for the number of comparisons. Shown only when the ANOVA is significant (p < 0.05) and there are at least three groups — unlike SPSS ONEWAY, which prints a requested posthoc table whatever the ANOVA shows.

Get it in your sheet

One formula in a cell gives the whole report, Ties included. ALS Stats is a free add-on for Google Sheets™.

Install ALS Stats from Google Workspace Marketplace (opens in a new tab)