Residual plot

luysion · #1 $Old$ June 27th, 2009, 06:22 AM

hey guys, just working on residuals. first post and hopefully not the last :P
so here the question much appriciation to however so helps

note- im finding it extremely hard to intrepret which is of random scatter and which is of a pattern.

which of the following residual plots shows that a linear model (the model used in the first place) is inappropriate to use to display the correlation between the two variables.

A)http://www.studyit.org.nz/phpBB2/download.php?id=6140
or
B) http://www.studyit.org.nz/phpBB2/download.php?id=6141

by the way hello

gd forums

pickslides · #2 $Old$ June 27th, 2009, 05:31 PM

The second residual plot has too many positive values to justitfy the regression suggested.

For the regression model to be stable the sum of residuals $\rightarrow 0$

luysion · #3 $Old$ June 27th, 2009, 06:37 PM

hey thanks pickslides,

just wondering though, in A can we state that there is no observable trend with the residuals? because it sort of seems like its got a decreasing trend, however the trend being extremely vague

pickslides · #4 $Old$ June 28th, 2009, 04:40 AM

You cannot determine an increasing or decreasing trend from a residual plot.

You are correct in saying the correlation is weak given the magnitude of each residual.