Question

A researcher designed a study to find out the effectiveness of two teaching methods: lecture-style vs. discussion-style. He compares the test scores of the students taught with these two different methods. The scores on the test range from 0 to 41 with higher scores indicating better performance. The test results are provided in the table below:

                                    Group       Methods                  n              M             SS
                                       1             lecture-style          15             24            336
                                       2             discussion-style    15             28             392

1. Do students taught with the discussion style perform better than those taught with the lecture style? Use the .05 significance level for the one-tailed test. Show the four steps of hypothesis testing, and describe the hypotheses and conclusion in words as well as notations

2. Compute (show calculation steps) and interpret r²

Answer 1

Let sample 1: lecture style

sample 2: discussion style

The sample standard deviations are

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Conclusion: There is evidence to conclude that students taught with the discussion style perform better than those taught with the lecture style.

(a)

The effect size r2 is

The effect size is small to medium.