2. A teacher is interested in comparing the effects of three different types of
ID: 2956740 • Letter: 2
Question
2. A teacher is interested in comparing the effects of three different types of rehearsal methods (Rote rehearsal, Imagery, and Story) on number of words recalled. Participants are randomly assigned into three different groups. In each group, participants are asked to study a list of words using the assigned method. The following table shows the result.Rote rehearsal Imagery Story
5 5 7
5 4 6
4 6 8
6 7 9
5 7 6
4 6 9
3 8 8
5 5 10
6 7 9
a. What statistical test should be used to analyze the data?
b. Identify H0 and Ha for this study.
c. Conduct the appropriate analysis.
d. Should H0 be rejected? What should the researcher conclude?
e. If there is a significant difference, conduct the post hoc test.
Explanation / Answer
a. What statistical test should be used to analyze the data? One-way ANOVA with = 0.05 b. Identify H0 and Ha for this study. Ho: There is no difference between the treatment means; that is, m1 = m2 = m3 Ha: At least one among m1, m2 and m3 is different from the other two. c. Conduct the appropriate analysis. Decision Rule: Reject H0 if the p- value < 0.05 See the Sheet ANOVA for the ANOVA table d. Should H0 be rejected? What should the researcher conclude? The p- value is almost 0. Since this is < 0.05, we reject Ho and accept Ha. We conclude that at least one of the three means is different from the other two. e. If there is a significant difference, conduct the post hoc test. Tukey's pair-wise p- values indicate that all the p- values are < 0.05. This means all the methods are significantly different in their efficiency. One factor ANOVA Mean n Std. Dev 6.296296296 4.8 9 0.97 Rote Rehearsal 6.296296296 6.1 9 1.27 Imagery 6.296296296 8.0 9 1.41 Story 6.3 27 1.79 Total ANOVA table Source SS df MS F p-value Treatment 47.19 2 23.593 15.54 4.69E-05 Error 36.44 24 1.519 Total 83.63 26 Post hoc analysis Tukey simultaneous comparison t-values (d.f. = 24) Rote Rehearsal Imagery Story 4.8 6.1 8.0 Rote Rehearsal 4.8 Imagery 6.1 2.30 Story 8.0 5.55 3.25 critical values for experimentwise error rate: 0.05 2.50 0.01 3.21 p-values for pairwise t-tests Rote Rehearsal Imagery Story 4.8 6.1 8.0 Rote Rehearsal 4.8 Imagery 6.1 .0308 Story 8.0 1.05E-05 .0034Related Questions
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