The median-median line for a set of data is y=-3.1x+2.4. What’s the residual for the point (-4, 15.2) ?

Question

The median-median line for a set of data is y=-3.1x+2.4. What’s the residual for the point (-4, 15.2) ?

Answer 1

observed value is 15.2

fitted regression line is: y = -3.1.x + 2.4

plug in value for x = -4 to get predicted value:

y = -3.1(-4) + 2.4 = 14,8

residual = observed - predicted = 15.2 - 14.8 = 0.4