24. Rosalie Friend (2001), an educational psychologist, compared three methods of teaching writing. Students were randomly assigned to three different experimental conditions involving different methods of writing a summary. At the end of the two days of instructions, participants wrote a summary. One of the ways it was scored was the percentage of specific details of information it included from the original material. Here is a selection from her article describing one of the findings:
The effect of summarization method on inclusion of important information was significant: F12, 1442 = 4.1032, p 6 .019. The mean scores (with standard deviations in parentheses) were as follows: Argument Repetition, 59.6% (17.9);
Generalization, 59.8% (15.2); and Self-Reflection, 50.2% (18.0). (p. 14)

(a) Explain these results to a person who has never had a course in statistics.

(b) Using the information in the preceding description, figure the effect size for the study.