Best R Help,

I like to estimate a Multinomial Logit Model with 10 Classes. The
problem is that the number of observations differs a lot over the 10
classes:

Class | num. Observations
A | 373
B | 631
C | 171
D | 700
E | 87
F | 249
G | 138
H | 133
I | 162
J | 407
Total: 3051

Where my data looks like:

x1      x2      x3      x4      Class
1       1,02    2       1       A
2       7,2     1       5       B
3       4,2     1       4       H
1       4,1     1       8       F
2       2,4     3       7       D
1       1,2     0       4       J
2       0,9     1       2       G
4       4       3       0       C
.       .       .       .       .

My model looks like:
estmodel <- multinom(choice ~ x1 + x2 + x3 + x4, data = trainset) 

When I estimate the model and use the resulting model for prediction of
'new' observations the model has a bias towards the Classes with a large
number of observations (A,B,D,J), the other classes are never predicted
by the model.

I thougth that the option "weights" of the multinom function could be
usefull but I am not sure how to use this in the above case.

Is there someone with experience regarding such a weigthing approach in
multinom? If someone could help me with suggestions it would be great!

Nice day,
Arne

______________________________________________
[email protected] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

Reply via email to