Question

A set of data points has a line of best fit of y=2.5x-1.5

What is the residual for the point (4,7)

Answer 1

Expect for x=4 is 2.5(4)-1.5=8.5
Residual=observed-expected=7-8.5=-1.5

Answer 2

Residual= -1.5

Explanation:

Given : Equation of line y=2.5x-1.5

To find : the residual for the point (4,7)

By definition of a residual is generally a quantity left over at the end of a process.

Now firstly we find the value of f at x=4

f(x) = 2.5x -1.5

f(4) = 2.5(4) -1.5

f(4) = 10 - 1.5

f(4) = 8.5

The residual for the point (4,7) At x=4 f(x)=7

At x=4 f(x)= 8.5

residual= 7-8.5 = -1.5