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?

–6.72
–0.58
0.58
6.72

Answer 1

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.

Answer 2

The data in the table is not shown here but here is the formula for the residual
residual = observed value - predicted value

To get the predicted value, you simply use the best fit equation:
y = 2.78x - 4.4

Substituting 4:
y = 2.78(4) - 4.4
y = 6.72

This value is subtracted from the observed value to get the residual.