Question

|A researcher was interested in whether there were |differences in the effect on performance on a stats exam among students who attended 1) office hours regularly 2) both office hours and review sessions, 3) just review sessions, and 4) neither office hours nor review sessions The researcher randomly assigned students to one of the four groups. At the end of the first exam, the researcher gave students in all four groups a stats exam and obtained the following results: Office & Review Office Review None 12 12 8 11 10 7 9 14 15 10 11 11 14 10 12 14 6 9 Xo 12, SSo 6 Xo&R 13, SSo&R =16 XR 8, SSR10X 9,SSy = 14 The researcher used an a-level of.05 to test her hypothesis

Answer 1

NULL HYPOTHESIS H0:

μι = μ2 = μ3 = μ4

ALTERNATIVE HYPOTHESIS Ha:Not all means are equal

alpha=0.05

By using Excel we have

Anova: Single Factor Count Sum Average Variance 60 SUMMARY Groups OFFICE OFFICE AND REVIEW REVIEW NONE 1.5 co ANOVA Source of Variation Between Groups Within Groups MS P-value Fcrit 3 28.3333333 9.855072464 0.00063982 3.238871522 2.875 16 Total 131

F cal= 9.86

Degrees of freedom df1= 3 and df2= 16

P value= 0.0006

Since P value smaller than the level of significance therefore SIGNIFICANT.

Decision: REJECT NULL HYPOTHESIS H0.

Conclusion: We have sufficient evidence to conclude that there is difference in means.