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.

model            N        MEAN      MEDIAN  TRI. MEAN     STD DEV    SE MEAN

hyumdai         23         109          135            107.64                *             1.34

toyota             27         165          124            143.65              9.5             **

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.

d) Assuming normality, construct and interpret a 90% confidence interval for the average monthly earning from Toyota Vehicles.
e) You are required to test at the 5% level of significance the hypothesis that the average monthly earnings on Hyundai Vehicles is equal to $110,000 versus the alternative that it is different from $110,000.