Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.



Test for Proportions/ttest
Posted:
Apr 8, 1997 5:36 PM


In teaching my classes, I've always stressed that under the usual assumptions with variance unknown, the ttest is appropriate and should always be used; however, a student recently posed a question which I could not answer. If doing a C.I. on proportions you don't know p, then you also don't know the variance. The question the students asked was Why don't we use the tvalue when we form a C.I. on a proportion?
There is a great deal of logic to their question since clearly p is not normal. Anyone with any ideas?



