Question

The scatter plot show the monthly balance in Mikes account for 2013. у 1200 1000 800 Balance (dollars) 600 400 200 0 2 4 6 8 10 12 Months since January 2013 Equation of the line of best fit is y = -44x + 1,000. x represents the number of months since January 2013. y represents the balance in the account. What is the correct interpretation of the slope of the trend line?

Answer 1

If the scatter plot shows on the vertical axis the balance in dollars, and on the horizontal axis the number of months starting in January 2013,

Then the line of best fit given by:

y = - 44 x + 1000 is representing a y coordinate in dollars and an x coordinate in months.

Then the slope which is normally defined as the "rise" over the "run" is given in units of "dollars" (for the rise in y coordinate) over "number of months" (x coordinate for the run).

Then the correct interpretation is the change in balance of the account per month. This means that the balance in the account when DOWN 44 dollars in average per month. Slope = - 44

The balance in the account reduced an average of $44 per month