[R] R - rpart - increasing xerror

[Daniel Blankenheim]

Hey
my name is daniel,  i am writing my bachelor thesis and wondering if you can
help me.
i am trying to generate a regression tree via  rpart. to
reduce the error of the model i use cross validation, but instead
of reducing the cross validation error (xerror) is increasing the more splits
there are.
I dont understand what that means. does it mean that my model doesnt fit the
data- that there is no trend in the data? i am 100% sure that
there must be a trend or correlation in the data.

> > please help me:)

> >         CP nsplit rel error xerror    xstd
> > 1 0.100022      0   1.00000 1.0192 0.14222
> > 2 0.066716      2   0.79996 1.3107 0.18720
> > 3 0.050471      3   0.73324 1.4127 0.21138
> > 4 0.033758      4   0.68277 1.5197 0.22826
> > 5 0.010376      5   0.64901 1.5360 0.23792
> > 6 0.000010      6   0.63864 1.5419 0.24280