Re: teaching statistical methods by rules?

[Jerry Dallal]

Robert Dawson wrote:
>     Exactly...  An example - we've been using Devore & Peck, which
> unfortunately introduces the Z test for the mean, supposedly for pedagogical
> reasons but without nearly a strong enough indication of this. A lot of
> students infer a rule "if n>30 use z rather than t" despite my repeated
> statements that Z is NEVER a better test for the mean under circumstances
> they are likely to encounter [in psychology]. Of course, if they are cutting
> lectures that day they won't hear the warning...

Okay, I'll bite.  Why?