11.46 ANOVA and taking notes: Researchers studied the type of note taking that would lead to the best performance on conceptual questions on a test (Mueller & Oppenheimer, 2014). Conceptual questions are those in which students have to apply the material, rather than just answer fact-based questions. Students were randomly assigned to one of the following groups: 1. Take notes by hand (the longhand group) 2. Take notes on their laptops as usual (the laptopnonintervention group) 3. Take notes on their laptops with instructions to try to put the notes in their own words (the laptop-intervention group) Because people tend to take notes verbatim on their laptops, the researchers speculated that those in the laptop-nonintervention group would learn less, on average, than those in the other two groups. The researchers reported that “results showed that on conceptual-application questions, longhand participants performed better (z-score M = 0.28, SD = 1.04) than laptopnonintervention participants (z-score M = −0.15, SD = 0.85), F (1, 89) = 11.98, p = 0.017, η 2 p = 0.12. Scores for laptopintervention participants (z-score M = −0.11, SD = 1.02) did not significantly differ from those for either laptop-nonintervention (p = 0.91) or longhand (p = 0.29) participants” (p. 1162).

a. What is the independent variable in this study? What are its levels?

b. What is the dependent variable in this study?

c. Is this an experiment or a correlational study? Explain your answer.

d. The report of the statistics provides us with z-score M rather than M. Explain what these researchers are reporting here.

e. Which groups are significantly different from each other? Describe two ways that we know this.

f. The effect size is given in terms of η 2 p . What does this tell us about the effect size? (Note: The subscript p means “partial” and indicates that this effect size is just for this particular finding. You may ignore the p in your answer. Remember that η 2 is roughly equivalent to R2 .) g. A friend hears this finding and says, “I don’t want to take notes longhand, but I’ll think about typing the notes in my own words. The mean z-score of −0.11 is higher than the mean z-score of −0.15.” Why is this statement problematic from a statistical point of view?

h. If the finding of no significant difference between the longhand group and the laptop-intervention group is wrong, what kind of error is this? Explain your answer.