Answer: 311 pounds
Explanation:
To find the average, add up all of the values and divide by the amount of values.
First add up all of the values.
322+290+321+326+330+315+311+292+290 = 2797
Now count how many values there are and divide your previous sum by it.
2797/9 = 310.78
Because you need to have 3 sig figs, round to the nearest one.
310.78 rounds up to 311.