22. In a One-way ANOVA, the "among group" variation is attributed to what source of variation? A. Unexplained variation B. Residual variation C. Experimental error D. Treatment effects 23. The Tukey-Kramer procedure is used for which of the following purposes? A. Test for differences in pairwise means. B. Test for normality of residuals. C. Test for independence of errors. D. Test for homogeneity of variances. 24. When the One-Way ANOVA result is significant, that is, the Ho will be rejected, a follow-up test must be performed to determine which particular pairs of groups significantly differ. The follow-up test procedure is referred to as A. Pair-by-pair t-tests. B. Multiple t-tests C. Post-hoc analysis D. Tukey's HSD Test 25. The correlation coefficient computed for the relationship between a dependent variable Y and an independent variable X is -0.35. This result means that A. 35% of the variation of the dependent variable Y is due to the linear relationship between Y and X. B. 12.25% of the variation of the dependent variable Y is due to the linear relationship between Y and X. C. There is a weak, negative relationship between Y and X. D. There is a very weak, negative relationship between Y and X. 26. Which of these correlations is the strongest? A. -0.71 B. 0.08 C. 0.62 D. -0.12 27. It measures how well the regression line represents the data and has values ranging from 0 to 1. A. r B. r^2 C. ? D. ?^2 28. What appropriate post-hoc analysis is to be done if the F ratio is significant and the number of observations per group is the same? A. Tukey's HSD test B. Scheffe's S test C. Tukey-Kramer procedure D. One-Way ANOVA

For nos. 29 to 32. Mr. Juan Rafael, the manager of JJ Computer Tech is conducting a study on the number of customers who pay by personal check, by credit card and by debit card. During the course of five days, he records the following number of purchases made by each method.

Check Credit Debit Card ANOVA Card 36 40 Source of 45 SS of MS Variation Fcomp 30 27 38 Among 718.9333 2 359.4667 groups 20 25 40 Error 564 12 47 15 35 47 Total 1282.933 14 20 26 35 Yi. 121 153 205 Pairs Absolute Mean Difference HSD value Description Check - Credit Card 6.4 Not significant Check - Debit Card 16.8 Significant Credit Card - Debit 10.4 Card Significant