The statistician of Sir K has developed the following cost-prediction equation, using observations from 12,000 to 30,000 machine hours: Y = P 236,837 +3.7625X R-squared = 0.81 Standard error = P 24,363 Several 'outliers' are noted within tolerable limits . . . Y (dependent variable) = total maintenance cost X (independent variable) = machine hours 30-A. What percentage of the variation in maintenance costs is explained by the independent variable? . 30-B. Compute the estimated maintenance cost at 20,000 machine hours.