On Dec 10, 2011, at 11:48 AM, tony333 wrote:
X8 = c(0.42808332, 0.14058333, 0.30558333, 0.09558333, 0.01808333,
-0.09191666, -0.11441666, -0.12941666, 0.13808333, -0.31691666,
0.25308333
,-0.20941666 ,0.02808333, -0.04441667, -0.43691666)
xy.lm = lm(Y~X8)
z = predict(xy.lm,list(X8=X8))
sz = coef(xy.lm)[1]+(coef(xy.lm)[2])*X8
is the same result in this step
but when use the prediction as
T8=c(-0.05691667, -0.09441666 , 0.31308333 ,-0.59941665 ,-0.33941666
,-0.64441665,-0.55691665 ,-0.01191667 ,0.22558333, -0.30691666 ,
0.97808331
, 0.49808332,-0.30941666 ,0.41808332 , 0.42308332)
zz = predict(xy.lm,list(T8=T8))
The first "T8" should be..^^ .... "X8"
> zz = predict(xy.lm,data.frame(X8=T8))
> ss = coef(xy.lm)[1]+(coef(xy.lm)[2])*T8
> identical(unname(zz), ss)
[1] TRUE
ss = coef(xy.lm)[1]+(coef(xy.lm)[2])*T8
here gives me different value and zz = z = sz i do not know the
reason for
that
what i understand about predict() act exactly like using coef() but
now do
not know the difference
If you give predict alist or data.fram whose name is different than
that of the origianl variable ist will be ignored.
thank you for respond
--
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