What is the purpose of residual plots?

Question

tkhunny · Answer

Visual inspection of patterns.  The premise is usually that the residuals are randomly distributed.  If you see something regular of predictable, something is seriously wrong.

anonymous · Answer

I have a couple of options on my homework, but several of them seem right.

perl · Answer

residual plots when you do line fitting?

anonymous · Answer

A. To determine caustation
B. To assess the type of relationship that exists between x and y
C. To check the appropriateness and fit of the regression equation for the data
D. To measure the variability in the residualss
E. To provide predictions for the response variable

anonymous · Answer

I can't decide between C and E!

tkhunny · Answer

What have you against each one?  One of them looks pretty compelling.

Why would residuals provide predictions?

anonymous · Answer

Well, I know that if the residual plot looks random, then a linear model is a good fit.

anonymous · Answer

I'm not particularly good at this area of math

tkhunny · Answer

Didn't you just quote "C"?

anonymous · Answer

I suppose I did, but E  looked particularly compelling! So I'm right, it is C?

tkhunny · Answer

Go with confidence!  Move on to the next one.

anonymous · Answer

Thanks for your help!