Moses test of extreme reactions
Compare how spread out two groups are after trimming extremes.
When to use it
Use the Moses test when you care about the range of scores in two groups, not the typical score. It trims a fraction of each group’s extremes and then compares the spans.
Assumptions
Exactly two groups. Each group needs at least two scores. Trim fraction starts at 0.05 and must sit between 0 and 0.25.
Running it in Tensr
Options
Prop
Type
Reading the output
The same two similar tutorial groups, asking whether one group has more extreme scores than the other.
Moses test of extreme reaction for score by group. Metrics: S statistic = 70; p-value = .500; Range ratio = 1.29; Range group 1 = 37.8; Range group 2 = 29.3.
The span after trimming is 70 and p = .500. The two groups do not differ in extreme reactions. That is the expected result for two samples drawn from the same spread.
Reporting (APA 7)
A Moses test of extreme reactions comparing score in groups A and B was not significant, S = 70, p = .500. The groups did not differ in spread.
Coming from SPSS
Analyze → Nonparametric Tests → Moses. SPSS prints a significance for the span. Tensr reports the span S, the p-value, and the two ranges.