A car company wants to know the monthly sales made in ($000), based on the brand of vehicle. The data collected was entered on a MINITAB spreadsheet for analysis. Exhibit II below was subsequently...

A car company wants to know the monthly sales made in ($000), based on the brand of vehicle.  The data collected was entered on a MINITAB spreadsheet for analysis. Exhibit II below was  subsequently generated.

Exhibit 2

a) Determine the values of * and **.

b) Give the unbiased point estimate for the average monthly earning from Hyundai Vehicles.
c) Give the unbiased point estimate for the variance of monthly earning from Hyundai Vehicles.