Rank and percentile are both measures used to assess performance relative to a group, but they have distinct meanings:

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   Rank: Rank indicates the position of a person's score in relation to all other scores. For example, if someone ranks 10th in a class of 100 students, it means there are 9 students who scored higher than them and 90 students who scored lower.

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   Percentile: Percentile, on the other hand, indicates the percentage of scores that are equal to or below a given score. For instance, if a student's score is in the 75th percentile on a test, it means their score is higher than 75% of the scores in the group.

In summary, rank is a specific position within a ranked list (1st, 10th, 50th, etc.), while percentile is a relative measure indicating how a score compares to the rest of the scores in terms of percentage.