20 14 Jiangxi senior high school entrance examination math questions a, gong, c, the average and variance of five math exam results are shown in the table, and the player with the most stable results is Suppose: E 1, E2 and E3 are the average scores of three people.

√ D 1, √ D2 and √ D3 are the standard deviations of the scores of three people.

Calculate the coefficient of variation: v 1 = √ d 1/e 1, v2 = √ d2/e2, v3 = √ d3/e3.

Compare which vi value is small and which student's grades are stable!