Re: teaching statistical methods by rules?

[Robert Dawson]

Jerry Dallal wrote:

>                                                        The problem for me
> with the statement "Z is NEVER a better test for the mean under
> circumstances they are likely to encounter [in psychology]" is that it
> reads like an indictment

    It is. The last thing students in Intro Stats need is one more red
herring.

> >     Caveat: Old fashioned t tables fashioned after the tradition the
> > Church
> > of the Holy 5% make it hard to compute p values that are not round
numbers.
>
>     So maybe z is sometimes better?

    Under certain artificial "desert island" scenarios, yes.  But:

>                                        In fact, it's hard to imagine
> circumstances where anyone dealing with real data will not be using a
> computer, if only to establish an audit trail.

          A new and different motive <grin>

>                                                         Since software
> insists on using t, the question is moot for all practical purposes.

    No, MINITAB (frinstance) will use Z if you insist. (And a pistol will
shoot you in the foot if you point it there & pull the trigger.) But it is
rarely the right thing to do.

    -Robert Dawson