Confidence level: what it means and how to read it
In the report: Level — The confidence level of the interval: ciLevel, 0.95 by default.
How to read it
0.95 means that in 95 samples of 100 an interval built this way would contain the true value.
In plain words
A baker weighed 30 loaves and the average was 500 grams. At the usual level, 0.95, the range for the true average loaf was 490 to 510 grams. This level means that if she weighed fresh loaves over and over, about 95 of every 100 ranges built this way would hold the true average. She wanted to be more careful, set the level to 99 ranges in every 100, and the range became wider: 485 to 515 grams. Now she can choose: a range 20 grams wide that holds the true average 95 times in 100, or one 30 grams wide that holds it 99 times in 100.
Example
The cell with Level is selected in each report; point at a label to see its note.
- — the sample data (50 rows) the examples use
- —
=STATS_SPEARMAN(Data!A1:T51, "x,y",0.95,"two-sided") - — x1 and x2 with age held constant
=STATS_PARTIAL(Data!A1:T51, "x1,x2", "age") - —
=STATS_PAIRED(Data!A1:T51, "before,after",0.95,"two-sided")
Where you see it
STATS_PEARSON— Pearson correlation (r).STATS_SPEARMAN— Spearman rank correlation (rho): the correlation for rating scales, ranks and skewed data — does one go up as the other goes up?STATS_KENDALL— Kendall rank correlation (tau-b): the correlation of the order of two columns — for small samples and scales with many tied answers.STATS_PARTIAL— Partial correlation: the Pearson correlation of two variables with the controls held constant (SPSS PARTIAL CORR). Two variables give one correlation, three or more a matrix, as STATS_PEARSON.STATS_PAIRED— Paired-samples t-test for two related measurements (e.g., pre vs post).STATS_INDEPENDENT— Independent-samples t-test for two groups: the two selected columns are the groups.STATS_ONE_SAMPLE— One-sample t-test against mu0.STATS_ANALYZE— Runs several analyses on one range and returns one report.
Related values
- Significance of the partial correlation — The p of the partial correlation, as SPSS names it, for the chosen alternative. Empty in the same cases as Correlation.
- Alternative hypothesis — The hypothesis tested: two-sided — the means differ in either direction; greater — the first is larger; less — the first is smaller.
- Exact significance — 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.
- Margin of error — Half the width of a two-sided interval: the t quantile times the standard error.
- Width of the interval — Upper − Lower.
Get it in your sheet
One formula in a cell gives the whole report, Confidence level included. ALS Stats is a free add-on for Google Sheets™.
Install ALS Stats from Google Workspace Marketplace (opens in a new tab)