The McMillans noticed that the amount of natural gas they use at their house each month is related to the average monthly temperature, as shown in this scatter plot.

Question

A scatter plot.Short description, A scatter plot.,Long description,
A scatter plot shows Average Monthly Temperature in degrees Fahrenheit on the x-axis and Amount of Gas Used in therms on the y-axis. The line of best fit is a line with a negative slope. Points are scattered on, above, and below the line.



Question
The slope of the line of best fit is negative 2.5 therms per degree.



Which explains how the slope can be interpreted?

Answer options with 4 options
A.
For each decrease of 10 degrees, the amount of gas used is about 25 therms less.

B.
For each increase of 10 degrees, the amount of gas used is about 25 therms less.

C.
For each decrease of 10 therms of gas used, the temperature is about 25 degrees less.

D.
For each increase of 10 therms of gas used, the temperature is about 25 degrees less.

Answer 1

The correct interpretation of the slope of the line of best fit, which is negative 2.5 therms per degree, is as follows:

When the average monthly temperature increases by 1 degree Fahrenheit, the amount of gas used decreases by 2.5 therms. Therefore, if the temperature were to decrease by 10 degrees, the gas usage would increase by 25 therms (since 10 degrees * 2.5 therms/degree = 25 therms).

Thus, the correct answer is:

A. For each decrease of 10 degrees, the amount of gas used is about 25 therms less.