Statistical Tests (More Than 2 Groups)

Question 1

One-way ANOVA

Answer 1

Whether the means of two or more sets of unrelatedmeasurements are different from each other (parametric)

Question 2

One-way ANOVA example

Answer 2

Whether one or more groups of experimentally treated organisms are different from controls

Or two or more species are different from each other (parametric data)

Question 3

Repeated Measures ANOVA

Answer 3

Test whether the means of a two or more sets of related measurements are different from each other

Question 4

Repeated Measures ANOVA example

Answer 4

Whether one group of experimentally treated organisms are different at several times before and after treatment

Or if two or more sets of measurements taken at known times are different from each other

Question 5

Two-way ANOVA

Answer 5

To analyse experiments or trials which you can look at the effects of two factors at once

Question 6

Two-way ANOVA example

Answer 6

Examining the effect of corn yield of adding different amounts of nitrate and phosphate

Or examining the effects on yield of adding different amounts of nitrate to more than one wheat variety (parametric data)

Question 7

ANOVA Post-Hoc tests

Answer 7

Tukey test and Dunnett test

Question 8

Tukey test

Answer 8

If you want to compare each group with all other groups (if ANOVA is significant)

Question 9

Dunnett test

Answer 9

If you want to compare experimental groups with a control

Question 10

Kruskal-Wallis test

Answer 10

Whether the medians of two or more sets of unrelatedmeasurements are different from each other

(non-parametric version of one-way ANOVA)

Question 11

Kruskal-Wallis test example

Answer 11

Whether one or more groups of experimentally treated organisms are different from controls

Or two or more species are different from each other (non parametric)

Question 12

The Friedman test

Answer 12

Whether two or more sets of related measurements are different from each other

(non-parametric version of repeated measures ANOVA)

Question 13

The Friedman test example

Answer 13

To test whether one group of experimentally treated organisms are different at several times after a treatment

Or if two or more sets of measurements taken at known times are different from each other

Question 14

Non-Parametric Post-Hoc tests

Answer 14

Dunnes test and Dunnett-Bonferroni test

Question 15

Dunnes test

Answer 15

To understand which groups are different from each other if the Kruskal Wallis or Friedman tests shows that their is a significant difference between groups

Question 16

Dunnett-Bonferroni test

Answer 16

If you want to compare experimental groups with a control if the Kruskal Wallis or Friedman tests shows that their is a significant difference between groups