A factory tracks the daily productivity of its workers. For each employee, for each day, it records the number of hours worked, and the number of units produced by the employee. A scatterplot of the data for a single day, relating these two variables, shows a linear trend with the fitted equation: Estimated Units = -2 + 15 hours.

1. Interpret the slope and intercept of the fitted line 
2. A carton contains 12 units. A working day at this plant has 8 hours. Describe the regression line if the data were converted to cartons produced (y) and days (or fractions of days) worked.
3. Would the R2 of the model in Part B be different from that in Part A?
4. What about the value of RMSE?