🚀 go-pugleaf

In article <1992Aug19.124712.305@ginger.hnrc.tufts.edu> jerry@ginger.hnrc.tufts.edu (Jerry Dallal) writes:
>In article <1992Aug18.214711.6657@mailhost.ocs.mq.edu.au>, wskelly@laurel.ocs.mq.edu.au (William Skelly) writes:
>> I am not sure I follow you.  From my applications I only want to test
>> some null-hypothesis (perhaps a narrow application...but very useful!).
>> Generally I want to know if two samples are from the same population.
>> Isn't this just asking whether or not the two sample means are close?
>> 
>
>Heck, *NO*!!!
>
>Suppose you have two safety devices.  Both are inexpensve to manufacture,
>install, and replace, compared to the consequences of their failure.  
>One has failure times that follow a
>normal distribution with a mean of 10 years and a standard deviation of 1 day.
>The other has failure times that follow a
>normal distribution with a mean of 10 years and a standard deviation of 
>3 years.  I hope you wouldn't be indifferent in choosing a 
>device to use when your test of significance fails to reject the null
>hypothesis of equal population means.

Thank you very much for this TRULY FINE example and explanation!
I just finished reading about sample characteristicts versus
population characteristics; I understood the material; but the cement
hadn't quite cured yet.  Thanks to your example, the material is now
fully cured and safe for use. ;-)

Tony Rizzo                  There's no shortage of engineers.
att.com!homxc!rizzo         There's only a shortage of engineering.