A graph question asking you to support an argument tests whether the data show every part of the claim. Read the claim first, and split it into parts. If it explains an overall result through the makeup of test groups, ask what each part needs to show. Read each panel’s title, axes, and key, then compare scores for the same kind of item and check the test groups’ makeup. Accurate numbers can still miss the claim when they don’t support all its parts.
Hints
- Hint 1
Read the statistician’s sentence and split the argument into two parts. What does it say caused the overall advantage, and what cause does it reject?
- Hint 2
In the accuracy panel, look for each system’s score on the same kind of page. What does that tell you about the cause the statistician rejects?
- Hint 3
Which page type has higher accuracy, and how could its share change an overall score? Use both panels together to test the statistician’s proposed cause.
Step-by-step
Test the page mix and accuracy
Step 1Split the statistician’s argument
Lumen’s overall lead was caused by the different proportions of printed and handwritten pages, the statistician argues. What else must supporting data show? The words not because Lumen was more accurate on either kind of page add another part, so the argument needs evidence about both the page mix and accuracy on each kind.
- Step 2
Compare the systems on each kind
The accuracy panel shows percentages, with a key identifying Lumen and Scribe. Does Lumen lead on either kind of page? On printed pages, Scribe scores 98% versus Lumen’s 96%; on handwritten pages, Scribe scores 74% versus Lumen’s 70%. Scribe is more accurate on both kinds, and both systems are more accurate on printed pages.
- Step 3
Explain how the mix changes the total
Why can Lumen lead overall despite its lower scores on both kinds? The composition panel measures proportions of printed and handwritten pages, not accuracy: Lumen’s test set is 80% printed, while Scribe’s is 30% printed. A page type with a larger share counts more toward the overall score. So Lumen’s score gives more weight to the higher-scoring printed pages, which explains how the page mix creates the overall lead.
- Step 4
Check the whole argument
Are true numbers enough to support the statistician's argument? Lumen's overall accuracy doesn’t compare the systems on each page type, while For both systems leaves out the test-set mix. Scribe was 4 percentage points more accurate leaves out the printed-page comparison. The choice beginning Scribe was more accurate than Lumen covers both page types and the page mix, so it supports the whole argument. Choice D.