SStot=165
Rsq=.6637
SSreg=Rsq*SStot
SSres=SStot-SSreg
npred=k=3
npoints=N=20
SEest=sqrt (SSres/(N-k-1))
SSvar=134.95
rsq = .1427
SEvar = sqrt (SEest^2/(SSvar*(1-rsq)))
