Levitt and Dubner support the claim with the reason: Sumo wrestlers who win eight or more matches earn a higher rank than those who do not. Which evidence supports this reason?

If the normal goal is to win matches, wrestlers finishing at 7–7 should have about the predicted win percentage in their final matches. A higher actual win percentage suggests that wrestlers near the eight-win cutoff may receive an extra win to reach eight victories and earn a higher rank. This supports the reason that winning eight or more matches leads to a higher rank; a wrestler with ten victories, as in choice A, is not near the cutoff.

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