The following excerpts from four regression analysis reports describe the relationship between a major operating cost and four cost drivers for Tory Corp. Regression Statistics Regression Statistics R-Sq Std. Error Observations 0.228 36.627 12 0.337 25.519 12 Std. Error Observations Coefficients Coefficients Intercept 1537.416 Intercept 1926.908 Labor Hrs 80.576 Machine Hrs 69.123 Regression Statistics Regression Statistics R-Sq Std. Error Observations 0.665 42.407 12 R-Sq Std. Error Observations 0.774 30.353 12 Coefficients Coefficients Intercept 1323.323 Intercept 1700.657 Customer Visits Kilowatt Hrs 46.822 23.409 Which cost driver is the best predictor of the operating cost? O Labor hours O Machine hours O Kilowatt hours Customer visits