Datum Plot 0.3.9

More statistics: three-way ANOVA, ANCOVA, agreement, bootstrap confidence intervals and spline fits.

Compare groups

• Three-way ANOVA: a grouped table whose rows are the first factor and whose data sets are named by two levels with a slash ("Young / Drug", "Old / Placebo"…). Main effects and every interaction, with effect sizes.
• ANCOVA: an XY table with the covariate in X and one data set per group. Checks that the slopes are parallel, then compares the groups' adjusted means (with Šidák comparisons) and draws the parallel lines on the graph.

Relationships

• Agreement: a contingency table of paired ratings (the first rating in the rows, the second in the data sets). Cohen's kappa with its 95% CI and strength, weighted for ordered categories, and McNemar's test (2 × 2) or Bowker's test (larger tables) for a systematic difference.

Statistics and fitting

• Bootstrap confidence intervals of each data set's mean, median or SD, and of the difference between the first two, without assuming a distribution (BCa, repeatable).
• Spline fit: Smooth has a smoothing spline whose smoothness is chosen automatically; it is drawn on the graph.

Fixed

• Double-clicking an item in the Analyze or Graph gallery now closes the gallery behind the window it opens.

Checked against independent results: kappa by its formula, McNemar's exact test by the binomial distribution, three-way sums of squares by hand, ANCOVA by nested models, the spline by SciPy.