Almost all on the 'heat' here - the flames - come from naive use or understanding of statistics,
either formal or rhetorical. Thanks for a good post.
"Michael Plog" <
[email protected]> wrote in message
news:Ibvua.813275$S_4.825722@rwcrnsc53...
> Concerning the statistical significance of a sample. A random sample means that every member of
> the population has an equal chance of being selected. Any sample is expected to vary from what
> would be obtained if the entire population were measured. This potential for variation is
> expressed in two concepts. First is the Confidence Level, second is the Estimated Error rate.
> Several formulae (the plural of "formula" can also be written "formulas") exist to determine what
> the confidence level and error rate of a sample. A search engine will provide you with some of the
> mathematics involved. This is not really the place to go through something like
> n=((t/e)**2*p(1-p))/1+1/N(..... you see the problem.
>
> Anyway, for the example you cited from the Census Bureau: For the population of almost 300
> million, a sample of over 9 thousand will give a Confidence Level of 99% with a tolerance for
> error between .01 and .02.
>
> Now, for the second thing that tends to bother professional statisticians and evaluators.
> Statistics will NOT say anything you want. An unscrupulous person can find or distort some number
> that supports an unreasonable position. The inaccuracies come from the misuse of statistics, not
> the mathematical implementation.
>
> Sorry to get on a high horse here, and I have not seen the field notes of the study. It is
> possible a malicious person biased the selection process or the wording of the questionnaire.
> However, the results that nearly three-quarters of the population wanted improvements for walking
> and cycling seem impressive to me. The idea that as people age they cycle less seems to fit my
> observational generalizations.
>
> One lesson from the survey may be to promote recumbents more aggressively among older people.
> Another lesson might be the encouragement of accessories designed for recumbent (older) riders,
> such as helmets with wider brims and clothing with side (not back) pockets.
>
> Enough said for now. I need to get a ride in before the rain hits.
>
> Thanks, Michael Plog
>
>
>
>
>
> "Blake McCully" <
[email protected]> wrote in message
news:[email protected]...
> > The US Census Bureau estimates the US population as 290,909,012 as
> of May 7,
> > 2003. A population of 9,600 was surveyed of 16 yr old and over.
> Without
> > excluding those under 16 from the estimated population, only 0.003 %
> of the
> > population (as of today not in 2002 when the survey was don) is statistically insignificant.
> >
> > Of course, as we all know, you can make statistics say anything you
> want.
> > I'm not sure what the point of the survey was? Any suggestions.
> >
> > B "John Riley" <
[email protected]> wrote in message
> >
news:[email protected]...
> > >
http://www.dot.gov/affairs/bts0703.htm
> > >
> > >
> > >
> > > --
> > > >--------------------------<
> > > Posted via cyclingforums.com
http://www.cyclingforums.com
> >
>