Question

The scatter plot shows the systolic blood pressure of people of several different ages. The equation represents the linear model for this data.

y = x + 95



According to the model, how much does the systolic blood pressure increase for each year of age?


1 mm Hg per year

5 mm Hg per year

15 mm Hg per year

95 mm Hg per year

110 mm Hg per year


A graph measuring systolic blood pressure in relation to age. A line indicates that blood pressure increases as age increases

Answer 1

Looking at the equation y= x + 95
We can see it is in the format y = mx + b,
where m represents the slope, or the rate of increase.

Since x is alone, it is assumed to be “1x”, with 1 being m, the slope.

Therefore the systolic blood pressure increases by 1 mm Hg per year.

Another way to solve this if you didn’t have the equation:

If we find two easy to pinpoint plots such as:
(0,95) (15,110)

The equation for slope is

x - x / y - y

15-0 / 110-95

= 15/15
= 1