Page 189 - Statistics II for Dummies

Chapter 10

Sorting Out the Means with

Multiple Comparisons

In This Chapter
▶ Knowing when and how to follow up ANOVA with multiple comparisons
▶ Comparing two well-known multiple comparison procedures
▶ Taking additional procedures into consideration

magine this: You’re comparing the means of not two, but k independent
Ipopulations, and you find out (using ANOVA; see Chapter 9) that you
reject Ho: All the population means are equal, and you conclude Ha: At least
two of the population means are different. Now you gotta know — which of
those populations are different? Answering this question requires a follow-
up procedure to ANOVA called multiple comparisons, which makes sense
because you want to compare the multiple means you have to see which
ones are different.
In this chapter, you figure out when you need to use a multiple comparison
procedure. Two of the most well-known multiple comparison procedures are
Fisher’s LSD (least significant difference) and Tukey’s test. They can help you
answer that burning question: So some of the means are different, but which
ones are different? In this chapter, I also tell you about other comparison pro-
cedures that you may encounter or want to try.

Note: For those individuals who come up with new multiple comparison pro-
cedures, the procedures are generally named after them. (It’s like having a
star named after you but less romantic and a whole lot more work.)

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