What is the Tukey-Kramer method?
In the Tukey–Kramer method, the minimum significant difference (MSD) is calculated for each pair of means. It depends on the sample size in each group, the average variation within the groups, and the total number of groups.
What is the Tukey-Kramer test used for?
Since the sample sizes are unequal, we use the Tukey-Kramer test to determine which pairwise comparisons are significant.
What is Q alpha in statistics?
The Studentized Range (q) is the difference between the largest and smallest data point in a sample, measured in terms of sample standard deviations. The shape of the studentized range distribution depends upon the context. For example, if you’re testing whether two means are equal, it is similar to the T distribution.
What is N in Tukey HSD?
The idea behind the Tukey HSD (Honestly Significant Difference) test is to focus on the largest value of the difference between two group means. The relevant statistic is. and n = the size of each of the group samples.
What is a good Q-value?
This is the “q-value.” A p-value of 5% means that 5% of all tests will result in false positives. A q-value of 5% means that 5% of significant results will result in false positives. Q-values usually result in much smaller numbers of false positives, although this isn’t always the case..
What is Q hypothesis testing?
In statistical hypothesis testing, specifically multiple hypothesis testing, the q-value provides a means to control the positive false discovery rate (pFDR). …
How is the Tukey Kramer test used in real life?
Note that the Real Statistics Tukey HSD data analysis tool described in Tukey HSD actually performs the Tukey-Kramer Test when the sample sizes are unequal. Example 1: Analyze the data in range A3:D15 of Figure 1 using the Tukey-Kramer test to compare the population means of women taking the drug and the control group taking the placebo.
How to perform a Tukey-Kramer post hoc test?
In order to find out exactly which groups are different from each other, we must conduct a post hoc test. The most commonly used post hoc test is the Tukey-Kramer test, which compares the mean between each pairwise combination of groups. The following example shows how to perform the Tukey-Kramer test in Excel.
When to use Tukey-Kramer method for unequal sample sizes?
In this case, one has to calculate the estimated standard deviation for each pairwise comparison as formalized by Clyde Kramer in 1956, so the procedure for unequal sample sizes is sometimes referred to as the Tukey–Kramer method which is as follows: where n i and n j are the sizes of groups i and j respectively.
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 .