A researcher wants to test the effectiveness of two differen

A researcher wants to test the effectiveness of two different computer-based instructional methods on teaching a unit on weather in seventh-grade science. The researcher finds a teacher who will permit three of his classes to participate: Two classes use the computer-based instruction, and the third receives conventional classroom instruction. The researcher administers a pretest to all students, each class has a different method of instruction, and then a post test is administered. a. Specify the design of this study and represent it using the notation system used in this chapter. b. What statistics would you choose to analyze these data?

Solution

To compare between two groups create null and alternate as

H0: All three groups are the same

Ha: Atleast two are different

Chi square two tailed test.

Prepare contingency table

Find chi square and df = (r-1)(c-1)

Here c = no of columns = 3

r = no of students in each class

If p value <alpha reject null hypothesis

Hence chi square statistic is to be chosen.