Post Hoc Comparisons

This lesson is called Post Hoc Comparisons, part of the Inferential Statistics with R course. This lesson is called Post Hoc Comparisons, part of the Inferential Statistics with R course.

Transcript

Click on the transcript to go to that point in the video. Please note that transcripts are auto generated and may contain minor inaccuracies.

Your Turn

Perform one-way ANOVA to test whether there is a difference in hs_gpa by grade_class. Is there a difference? If so, perform a Tukey’s HSD to test where the differences are. Describe the differences.
Perform one-way ANOVA to test whether there is a difference in weight_2 by gender. Is there a difference? If so, perform a Tukey’s HSD to test where the differences are. Describe the differences.

Learn More

Read more about the tukey_hsd() function in the rstatix package. The rstatix package also has functions for Dunn's test of multiple comparisons using dunn_test(), Games Howell post-hoc tests using games_howell_test(), and pairwise comparisons of estimated marginal means using emmeans_test().

Have any questions? Put them below and we will help you out!

You need to be signed-in to comment on this post. Login.

Mike LeVan • January 7, 2025

For the second problem in Your Turn, how can we interpret the results? What does it mean that weight_2 and the female and male gender are statistically significant? Thanks.

David Keyes Founder • January 8, 2025

I'm not sure of the answer, but I've asked Dana to respond. Hopefully that will happen soon!

Dana Linnell • January 9, 2025

Hi Mike, because there is only one significant Tukey HSD (Female vs Male, p = .001) you would say something like (note that the APA style italicization can't be shown here): There was a significant difference in weight by gender, F (2, 297) = 6.41, p = .002, ges = .041. Tukey's HSD revealed that there was a significant difference in weight between males (M = fill in the blank, SD = fill in the blank) and females (M = fill in the blank, SD = fill in the blank; p = .001) but no difference between trans individuals with males or females by weight.