Contents
- 1 How does a Tukey test differ from other multiple comparison tests?
- 2 What statistical distribution do we use for the Tukey Kramer multiple comparisons?
- 3 When to use Tukey adjusted comparisons in emmeans?
- 4 How does Tukey’s test apply to all pairwise comparisons?
- 5 How is the Tukey range test similar to the t-test?
How does a Tukey test differ from other multiple comparison tests?
It controls FWER after considering every possible pairwise combination, whereas the Tukey test controls the FWER when only all pairwise comparisons are made. This is why the Scheffé’s method is very conservative than other methods and has small power to detect the differences.
What statistical distribution do we use for the Tukey Kramer multiple comparisons?
The Tukey method uses the studentized range distribution. Suppose we have r independent observations y1., yr from a normal distribution with mean µ and variance s2.
What is the difference between the follow up procedures of Bonferroni and Tukey?
Bonferroni has more power when the number of comparisons is small, whereas Tukey is more powerful when testing large numbers of means.
When to use Tukey adjusted comparisons in emmeans?
Also note that the “Tukey” in glht has nothing to do with Tukey HSD or Tukey-adjusted comparisons; it just sets up the contrasts for all pairwise tests, as the output says. However, the adjust=”tukey” in emmeans functions does mean to use Tukey-adjusted comparisons, as the output says.
How does Tukey’s test apply to all pairwise comparisons?
Tukey’s test compares the means of every treatment to the means of every other treatment; that is, it applies simultaneously to the set of all pairwise comparisons.
How are sum of squares calculated in Type II?
Type-II sums of squares are calculated as follows: First, compare a model with only factor 2 to a model with factor 1 and 2. Next, compare a model with only factor 1 to a model with factor 1 and 2. Finally, compare the full model with both factors and interaction to the model with only factor 1 and factor 2.
How is the Tukey range test similar to the t-test?
There is equal within-group variance across the groups associated with each mean in the test ( homogeneity of variance ). Tukey’s test is based on a formula very similar to that of the t -test. In fact, Tukey’s test is essentially a t -test, except that it corrects for family-wise error rate .