| Date: | Sat, 30 Jul 2011 08:09:47 -0400 |
| Reply-To: | Paul <johnsaxo@GMAIL.COM> |
| Sender: | "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU> |
| From: | Paul <johnsaxo@GMAIL.COM> |
| Subject: | Predictive model for rare event |
|---|
Hi everyone,
I would like to build a predictive model(Logistic regression or decision
tree or NNet . But the frequency of the event I am predicting is extremely
small less than 1%.
In fact here is my frequency distribution of my dependent variable
Churn_ind
Churn_ind=1 150(0.75%)
Churn_ind=0 19850(99.25%).
Questions:
Q1: What is the minimum sample size to run a reliable model?
Q2: What model could best fit this type of distribution where my event is
less than 1% and in this case 150 out of 20000 ?
Q3:Is there a minimum N sample size when running a decision Tree I tried
to run a decision but got no results.
I turning to the group here to seek for ideas . Your assistance is more
more than welcome.
Thanks,
Paul
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