Question

the scatter plot and trend line show the average income, in dollars, in several major american cities plotted against the rent for a 2 - bedroom apartment in those cities. assuming the line correctly models the trend in the data, what does this lines slope of 0.031 mean?
choose 1 answer:
a the average house for rent is 0.031 million square feet.
b the average rent was 0.031 thousand dollars.
c on average, each $1 increase in average income was associated with a $0.031 increase in average rent.
d on average, each $0.031 increase in average income was associated with a 1 point increase in average rent.

Explanation:

The slope of a line in a scatter plot (with average income on the x - axis and rent on the y - axis) represents the rate of change of y with respect to x. Here, the slope is 0.031. So, for each unit increase in the x - variable (average income, in dollars), the y - variable (rent, in dollars) increases by the slope value. Option A is incorrect as slope has nothing to do with square feet of the house. Option B is incorrect as it misinterprets what the slope represents (it is not the average rent value). Option D has the relationship reversed (it should be income increase associated with rent increase, not the other way around with the values as given). Option C correctly states that for each $1 increase in average income, the average rent increases by $0.031.

Answer:

C. On average, each $1 increase in average income was associated with a $0.031 increase in average rent.