Degrees of freedom between groups: what it means and how to read it
In the report: dfBetween — The first degrees of freedom of F: the number of groups minus 1.
How to read it
The first number in brackets after F: the number of groups minus one. With 3 groups it is 2.
In plain words
A teacher wrote a report about three ways of teaching. Next to the main result of her test she saw two small numbers and did not know what the first one meant. She looked up the degrees of freedom between groups and found 2. Now she knows it is always one less than the number of groups: three groups give 2, five groups would give 4. She copies it into the report in its usual place, and any reader can see how many groups she compared. She does not have to explain it or read anything more into it.
How it is computed
dfBetween = k − 1Example
The cell with dfBetween is selected in each report; point at a label to see its note.
- — the sample data (50 rows) the examples use
- — classic one-way ANOVA
=STATS_ANOVA(Data!A1:T51, "x1,x2") - — new syntax, 3 reports
=STATS_ANALYZE(Data!A1:T51, "PAIRED('before,after', 0.99, 'greater') ANOVA('x1,x2,x') DESCRIPTIVE('mean,std,n', 'x1,x2')")
Where you see it
STATS_ANOVA— One-way ANOVA: each selected column is a group. Classic (Student) or Welch ANOVA, chosen by welch (auto by default), with homogeneity of variances and post-hoc comparisons.STATS_ANALYZE— Runs several analyses on one range and returns one report.
Related values
- Degrees of freedom within groups — The second degrees of freedom of F. For the classic test — all values minus the number of groups; for Welch it is smaller and usually fractional.
- Degrees of freedom 1 — The first (numerator) degrees of freedom of the F statistic next to it.
- Degrees of freedom 2 — The second (denominator) degrees of freedom of the F statistic next to it.
- Degrees of freedom — The degrees of freedom of the statistic next to it: how much independent information the estimate rests on.
- t statistic — A difference measured in standard errors; its sign is the sign of the difference. Its p comes from the t distribution with the degrees of freedom next to it.
Get it in your sheet
One formula in a cell gives the whole report, Degrees of freedom between groups included. ALS Stats is a free add-on for Google Sheets™.
Install ALS Stats from Google Workspace Marketplace (opens in a new tab)