[Prev][Next][Index][Thread]

Re: NMA STUDY



In article <3uvgn2$2gt@news-e1a.megaweb.com>, kennystar@megaweb.com 
(KENNY MORSE) writes:
> One of the questions
> I ask EVERY class I teach is if their speeding ticket had anything to do with
> the fact that they were "in a hurry".  Well over 75-80% of them raise their
> hands.  

This is a very biased sample!  It seems to me that drivers "in a
hurry" are more likely to take obvious risks that get the attention of
the cops (and hence land in your classes).  

Also note that choosing to go to traffic school is a form of 
self-selection.  I don't know the motivations for going to traffic 
school, so I don't know how this self-selection process would further 
bias your sample (it already having been biased toward "those who get 
tickets"), but it seems to me that some additional bias is inevitable 
here.  

I would be very damned careful about drawing conclusions about the 
general driving public from an informal polling of such a biased 
sample.  

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet: jeh@cmkrnl.com (JH645)  CompuServe: 74140,2055  


Follow-Ups: References: