Question

Maria gathered the data in the table. She finds the line of best fit to be y = 2.78x – 4.4. What is the residual value when x = 4?

Answer 1

Solution:

The line of best fit is given as y=2.78x-4.4

We need to find the residual value when x=4.

The residual value is  an estimate of the wholesale value .To find the residual value we plug in x=4 in the given line of best fit.The corresponding y value will give the predicted  value.

y=2.78x-4.4

Substituting x=4,

y=2.78(4)-4.4

y=11.12-4

y=7.12.

The predicted value when x=4 is y=7.12.

Residual value = predicted value  - Actual value -=7.12 - actual value.

Answer 2

The correct answer would be C.0.58

You plug 4 into the line of best fit and get 6.72. This is your predicted value, but the residual is the difference between the actual value and predicted. So you subtract: 7.3-6.72=0.58.