Question

Rani went around the laboratory where she works and measured her coworkers' ear circumference (in millimeters). Then she matched her results with each coworker's age and created the following scatterplot and regression line. The fitted line has a slope of 0.48. What is the best interpretation of this slope?

1) The ear circumference increases by 0.48 millimeters for every unit increase in age.
2) The ear circumference decreases by 0.48 millimeters for every unit increase in age.
3) The ear circumference increases by 0.48 millimeters for every 10 units increase in age.
4) The ear circumference decreases by 0.48 millimeters for every 10 units increase in age.

Answer 1

The slope of 0.48 means that for every year of age increase, the ear circumference increases by 0.48 millimeters on average.

Step-by-step explanation:

The best interpretation of the slope of 0.48 in Rani's regression line relating ear circumference to age is that the ear circumference increases by 0.48 millimeters for every unit increase in age. This means that as coworkers at Rani's laboratory get older, on average, their ear circumferences are expected to increase by nearly half a millimeter per year.