Re: When to Use t and When to Use z Revisited

[Robert J. MacG. Dawson]

Ronny Richardson wrote:
> 

> Are they
> 
> 1. Wrong
> 2. Just oversimplifying it without telling the reader

        Neither, really. The MAIN objection to "z over 30" is that it adds an
an unnecessary step to the decision process. If it actually simplified
things greatly I reckon we could live with the slightly wonky p-values
(as we do when we use ANOVA in the knowledge that we do not have perfect
homoscedasticity).  But it makes things more complicated...

        A true cynic might say that there is one advantage to keeping the
procedure in the textbooks - it wil occasionally give the readers of
articles warning that the writer has learned statistics by rote.

        -Robert Dawson


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