Heights of grade school repeaters. Refer to the Archives of Disease in Childhood (Apr. 200...

Heights of grade school repeaters. Refer to the Archives of Disease in Childhood (Apr. 2000) study of whether height influences a child’s progression through elementary school, presented in Exercise 7.15 (p. 367). Within each grade, Australian schoolchildren were divided into equal thirds (tertiles) based on age (youngest third, middle third, and oldest third). The researchers compared the average heights of the groups, using an analysis of variance. (All height measurements were standardized with z-scores.) A summary of the table at the top of the page:

a. What is the nullhypothesis for the ANOVA of the boy’s data?

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b. Interpret the results of the test. Part a. Use α = 0.5.

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c. Repeat parts a and b for the girl’s data.

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d. Summarize the results of the hypothesis tests in the words of the problem.

Exercise 7.15