A study was done to investigate the relationship between a new anti-inflammatory medicine and weight gain. The correlating linear model is shown below, where x represents the number of days on the medicine, and y represents the weight gain, in pounds. Interpret the slope.

Question

A.
An additional 0.7 days on the medicine is associated with a pound of weight gain.
B.
An additional day on the medicine is associated with 0.7 pounds of weight gain.
C.
Zero days on the medicine is associated with 0.7 pounds of weight gain.
D.
Not enough information is provided to interpret the slope.

Answer 1

The slope of a linear model indicates the expected change in the dependent variable (y) for a one-unit increase in the independent variable (x). In this case, for each additional day (x) on the medicine, the weight gain (y) changes by the slope value.

Since the slope is stated as being 0.7 in your context, the correct interpretation is:

B. An additional day on the medicine is associated with 0.7 pounds of weight gain.

This means that for each day a person is on the medicine, we expect their weight to increase by 0.7 pounds.