Use the information to answer questions 13 and 14 To compare the amount of time spent on recent service calls with the total amount charged for labor and parts, a repairman uses a scatter plot. He draws a line with the equation \( y=47.5 x+250 \) to model the data, where x is the time in hours spent on a call, and y is the total amount charged in dollars.

Did you know that scatter plots can tell a story about relationships? In our case, the equation \( y=47.5 x+250 \) indicates that for every additional hour spent on a service call, the total charge increases by $47.50. The $250 represents a base fee, possibly for the initial assessment or minimum service charge. This helps clients understand how time translates into money! When using scatter plots, a common mistake is to misinterpret the slope and y-intercept. In this model, some might think the y-intercept means that $250 is the charge per hour, but it actually reflects the minimum cost regardless of time spent. To avoid confusion, always clarify the meaning of the variables and the context in which they apply!