18. (10 points) Continuing with Valve Inc. data in the previous problem, assume Valve Inc. budgeted a 8.75% share sales of total H, J and A valves in the local market. Reliable industry data indicates that the actual total number of H, J and A valves sold in the same period was 6,875,000 valves.

a. Compute the market-share variance for the period. b. Compute the market-size variance for the period.