Question about Cubist Model

On Jan 12, 2017, at 5:37 PM, Lorenzo Isella <lorenzo.isella at gmail.com> wrote:

Dear All,
I am fine tuning a Cubist model (see
https://cran.r-project.org/web/packages/Cubist/index.html).
I am a bit puzzled by its output. On a dataset which contains 275
cases, I get non mutually exclusive rules.
E.g., in the output below, rules 2 and 3 cover all the 275 cases of
the data set and rule 1 overlaps partially.
Am I misunderstanding something?

Many thanks

Lorenzo




Cubist [Release 2.07 GPL Edition]  Thu Jan 12 23:10:40 2017
---------------------------------

  Target attribute `outcome'

Read 275 cases (21 attributes) from undefined.data

Model:

Rule 1: [204 cases, mean 0.5393324, range 0 to 2.285714, est err
0.2598495]

  if
   home_copub_after_all <= 0.7142857
      host_copub_after_all <= 1.833333
        then
        outcome = 0.1666667 + 0.9 home_copub_after_all
                 + 0.11 home_copub_before_all

Rule 2: [259 cases, mean 0.7445303, range 0 to 3.166667, est err
0.1866440]

  if
   host_copub_after_all <= 1.833333
       then
       outcome = 0.0433333 + 0.75 home_copub_after_all
                     + 0.33 host_copub_after_all + 0.37
   top_10_after_all

Rule 3: [16 cases, mean 4.4285712, range 2.142857 to 8.857142, est
err 1.0346190]

  if
   host_copub_after_all > 1.833333
       then
       outcome = 1.595 + 1.03 top_10_after_all + 0.45
   home_copub_after_all


Evaluation on training data (275 cases):

  Average  |error|          0.2678023
      Relative |error|               0.38
       Correlation coefficient        0.94


       Attribute usage:
                   Conds  Model

             100%    54%    host_copub_after_all
                      43%   100%
                      home_copub_after_all
                             57%
                      top_10_after_all
                             43%
                      home_copub_before_all


Time: 0.0 secs