Tina's application for graduate school was ranked 56 out of 400 applications. Her twin sister's application to a different graduate school was ranked 15 out of 300 applications.

a. Which sister had the higher percentile ranking?

b. If you had the data on the cumulative GPA of each school's students in June 2019, which measure of average would be the most meaningful - mean, median, mode? Explain.

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