10.7 - Lesson 10 Summary


Upon successful completion of this lesson, you should be able to:

  • Explain why it is not appropriate to conduct multiple independent t tests to compare the means of more than two independent groups
  • Use Minitab to construct a probability plot for an F distribution
  • Use Minitab to perform a one-way between groups ANOVA with Tukey's pairwise comparisons
  • Interpret the results of a one-way between groups ANOVA
  • Interpret the results of Tukey's pairwise comparisons

In this lesson you learned how to compare the means of three or more groups using a one-way between groups ANOVA. A one-way between groups ANOVA is used instead of multiple independent \(t\) tests in order to avoid increasing the likelihood of committing a Type I error.

An ANOVA provides information about the explanatory variable overall, but not about differences between the different levels of that variable. In order to compare the different pairs we need to conduct a post-hoc analysis such as Tukey's HSD test.