Question

13)	Post-hoc tests in a one-way ANOVA are conducted only if: I. There are more than two levels on the independent variable II. The F-ratio is significant III. The sample size is large enough IV. There is a significant interaction
	a) II, III and IV b) I, II and IV c) II and IV d) I and II e) I, II and III .

Answer 1

The correct answer is (D) I and II

Explanation-

Means Post-hoc tests in a one-way ANOVA are conducted only if:

I. There are more than two levels on the independent variable Because One way ANOVA is used when there are more than two levels of one independent variable to avoid multiple t-test calculations.  So, post hoc test in a one way ANOVA needs more than two levels of IV. one way ANOVA explains whether there is an overall significant difference among means or not but not about which specific groups differ but post hoc test does tell about which specific groups differs.

II. The F-ratio is significant- To calculate and apply post hoc, first, it is mandatory criteria that f- ratio should be significant.

Incorrect options-

III. The sample size is large enough- There is no defined minimum size of the sample to calculate the post hoc test. suppose if there are 3 groups, it means k=3 then the required n= k+1 only so, n= 3+1=4 so, two groups will have one subject and the third group consists of 2 subjects.

IV. There is a significant interaction- There is no study of interaction in one way ANOVA because there is only one independent variable.