Exact significance: what it means and how to read it
In the report: Exact Sig. — The exact p of U (Dineen and Blakesley), shown only for small groups without ties, as SPSS; for a two-sided test twice the one-tailed p.
How to read it
A more exact p for small groups without ties — shown only then. When you see it, report this p instead of Asymp. Sig.
In plain words
A teacher compared two small groups of 5 students, and no two scores were the same. The usual chance number, Asymp. Sig., is only a close guess that works well for big groups, so she did not fully trust it. The report also showed Exact Sig., worked out without any guessing. It appears only for small groups with no equal scores. The close guess said about 4 times in 100, and Exact Sig. gave 0.032, about 3 times in 100. Both are below the usual 5 times in 100, but she writes the exact one in her report, since it is the fair answer for groups this small.
Example
The cell with Exact Sig. is selected in each report; point at a label to see its note.
- — the sample data (50 rows) the examples use
- — with the Chi-Square Tests and Symmetric Measures tables at the end
=STATS_CHI2(Data!A1:T51, "gender", "group", TRUE)
Where you see it
STATS_CHI2— Pearson chi-square test for association between two categorical columns.STATS_MANN_WHITNEY— Mann–Whitney U test for two independent samples — the rank replacement for STATS_INDEPENDENT when the data are not normal (see STATS_NORMALITY), are ranks or rating scales (1–5), or have outliers.
Related values
- Margin of error — Half the width of a two-sided interval: the t quantile times the standard error.
- Width of the interval — Upper − Lower.
- Estimate within the interval — TRUE (1) when the slope of the data lies inside the interval.
- p-value — The probability of a result at least this extreme if there were no effect (if the null hypothesis held).
- Adjusted p of the pair — The p of the pair corrected for the number of comparisons by the posthoc method.
Get it in your sheet
One formula in a cell gives the whole report, Exact significance included. ALS Stats is a free add-on for Google Sheets™.
Install ALS Stats from Google Workspace Marketplace (opens in a new tab)