Question

An investigator conducts an experiment involving the effects of three levels of a drug on memory. Subjects are randomly assigned to one of three conditions. A different drug level is administered in each condition. Memory is measured 10 minutes after each subject receives the drug. The following scores are recorded. The higher the score, the better the memory.

given X1=9.00, X2=9.50 X3=15.25, n=4 MSwithin=6.639, dfwithin=9 , dfbetween=2, k=3 And given the following values obtained from ANOVA X1=36, X2=38, X3=61, n1=n2=n3=4, k=3, dfbetween=2, dfwithin=9, MSwithin=6.639

1. Compare groups 2 and 3 using a planned comparison and a nondirectional H_{1 .}
2. What are the df for a planned comparison?
3. With a planned comparison using an α = 0.05, what is the appropriate t_crit ?
4. Conduct a post hoc between groups 2 and 3 using the Scheffe test.
5. Calculate MS_{between (groups 2 and 3)} .
6. Calculate F_{scheffe (groups 2 and 3)} .
7. Using the Scheffe test with α = 0.05, what do you conclude?
8. When doing multiple comparisons, which method is the most powerful, planned or post hoc?

Answer 1