Rounded to the nearest 3 decimal places, what is the value of r for this data set?

Using geogebra (see attached), I get roughly r = 0.98886 which rounds to r = 0.989

0.989

Side Note: The fact that r is very close to +1 means the data set has strong positive linear correlation. The points all fall very close to a line with positive slope. 

Perpendicular lines have slopes that are the negative reciprocals of each others slopes. this means that you can:
1. write the slope as a fraction (if not already one),
2. flip the fraction over
3. multiply the fraction by - 1
4. And you have perpendicular lines slope.

so the slope of this line is - 1 so:
1. - 1 = - 1/1 convert to fraction
2. - 1/1 = - 1/1 flip but this case stays same
3. - 1/1 * - 1 = 1 multiply by - 1
4. slope is 1

we have slope and point so we can plug into equation:
y = mx + b
with m as slope and b is y intercept.

plug values:
4 = 1 * (- 2) + b
6 = b

so y intercept would be (0,6)