Question

Find an Equation for the least squares line then use it to find the missing value.

(400, 50)
(500, 65)
(500, 70)
(600, 80)
(700, 85)
(800, 95)
(550, Y)
Interpolate

I think the least squares line is y= .10538X+ 12.6923
Could someone verify and please instruct me how to complete the rest? What does it mean by interpolate?

Answer 1

Hmmm. Once you have an equation for the line, which you have, there's no need to interpolate. You can just plug in 550 for x.

Now, if you don't have a function, but just data points, then you need to interpolate. That is, use the slope between two points to estimate an intermediate value.

For example, you have
700,85
800,95

Now, if you want to estimate y when x is 750, then you interpolate by saying

750 is half the way from 700 to 800.
SO, y will be half the way from 85 to 95, or 90.