Displaying 1 result from an estimated 1 matches for "intracrani".
Did you mean:
intracranial
2008 May 29
2
Plotting a cubic line from a multiple regression
Dear all,
I'm attempting to plot a cubic relationship between two variables
controlling for the effects of a third variable. In this short
example, I'm trying to use AGE to predict CORTEX while controlling for
the effects of TIV (total intracranial volume):
########################
cortex = rnorm(100, mean=0.5, sd=0.5)
age = rnorm(100, mean=10, sd=2)
tiv = rnorm(100, mean=1000, sd=100)
##
## simple regression (ignoring TIV) works
##
cortex.lm = lm(cortex ~ poly(age, degree=3))
plot(age, cortex)
pseudo.x = seq(min(age)-2, max(age)+2, len=2...