The achievement test scores for four different groups of students, each group taught under different conditions, are shown in Table 15.9. The experimenter wants to test the hypothesis of no difference in the population distributions of achievement test scores versus the alternative that they differ in location; that is, at least one of the distributions is different from the others.

Conduct the test using the Kruskal–Wallis H-test with a 5.05.

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Table 15.9 Test Scores (and Ranks) under Four Different Conditions 1 2 3 4 65 (3) 75 (9) 59 (1) 94 (23) 87 (19) 69 (5.5) 78 (11) 89 (21) 73 (8) 83 (17.5) 67 (4) 80 (14) 79 (12.5) 81 (15.5) 62 (2) 88 (20) 81 (15.5) 72 (7) 83 (17.5) 69 (5.5) 79 (12.5) 76 (10) 90 (22) Rank Sum T-63.5 T =89 T =45.5 T =78