First of all, you should understand that the standard deviation can reflect the dispersion of a set of data.

The average value indicates the degree of stability.

So find the average and variance of medals in three years respectively.

~2 stands for the square of 2, * stands for multiplication symbol,/stands for division symbol or semicolon.

The average number of medals in three years is (28+32+51+16+17+21+15+14+18)/.

The medal variance is equal to1/9 * {(28-23.55) ~ 2+(32-23.55) ~ 2+(51-23.55) ~ 2. . . + ( 18-23.55)~2}=Q

Then the standard deviation is the arithmetic square root of variance, which is equal to Q under the root sign.

So p is greater than or equal to the average +q under the root sign, and p is less than or equal to the average +q under the root sign.

Remember to use rounding.