Question 20·Medium·Command of Evidence
Psychologist Lena Ortiz and colleagues investigated whether spaced practice (reviewing material in multiple sessions separated by time) leads to better long-term learning than massed practice (reviewing the same total amount of time in one session). The researchers randomly assigned 180 high school students to one of three groups. The spaced-practice group studied 30 vocabulary word pairs for 10 minutes on three different days. The massed-practice group studied the same 30 word pairs for 30 minutes in one session. The control group studied the word pairs for 10 minutes in one session. One week later, all students took a test asking them to recall the second word in each pair. After analyzing the results, the researchers concluded that spaced practice improved long-term recall.
The graph shows the average number of word pairs recalled correctly by students in each group.
Which choice best describes data in the graph that support the researchers’ conclusion?
For command-of-evidence questions tied to a graph, restate the researchers’ conclusion in your own words, then identify exactly what data pattern would support it (for example, one group’s average being highest). Next, compare the relevant bars and choose the option that describes that specific pattern; eliminate options that are merely true but don’t directly support the conclusion or that describe the wrong comparison.
Hints
Match the conclusion to a pattern in the data
Look for the group that should have the highest average if the researchers’ conclusion is right.
Compare the bar heights
Check whether the spaced-practice bar is higher than the massed-practice bar and the control bar.
Avoid choices that are true but too general
Some options may describe the graph accurately without directly supporting the specific claim about spaced practice.
Step-by-step Explanation
Identify what would support the conclusion
The conclusion says spaced practice improved long-term recall, so the key evidence should show that the spaced-practice group recalled more word pairs than the other groups.
Compare the groups’ averages in the graph
In the graph, the spaced-practice bar is the highest (about 25 word pairs), while the massed-practice and control bars are lower (about 22 and about 21.5, respectively).
Select the choice that matches that comparison
The choice that states the spaced-practice group recalled more word pairs on average than the other two groups is correct: Students in the spaced-practice group recalled more word pairs correctly on average than students in the other two groups did.