The average value of the squared speed v2 does not equal the square of the average speed

Question:

The average value of the squared speed v̅2 does not equal the square of the average speed (v̅)2. To verify this fact, consider three particles with the following speeds: v1 = 3.0 m/s, v2 5 7.0 m/s, and v3 = 9.0 m/s. Calculate (a) v2 = 1/3 (v12 + v22 + v32 ) and (b) (v̅)2 5 [1/3 (v1 + v2 + v3 )]2.