Sounds good. If my data permitted it I would want to do a dependent t-test, correct? Thanks, Jason

Quoting Peter Flom <peterflomconsulting@mindspring.com>:

> J M <jasonm@UCLA.EDU> wrote >>> >>> HOWEVER, with n = 4,500, a tiny difference will be statistically >>> significant. Will it be of any importance? >> >> So, if I have 20% respond "yes" in 2008 and then 22% respond "yes" in >> 2009 I can say that due to the large sample the difference would most >> likely be statistically significant if we had the correct data to >> actually test this claim? >> > > You can do an independent sample t-test of proportions, ignoring the > matching. This is easy enough > to do by hand, with the formula for a t-test. > > Or you can do a chi-square test: > > data today; > input year $ yesno $ count; > datalines; > 2009 yes 990 > 2009 no 3510 > 2008 yes 900 > 2008 no 3600 > ; > run; > > proc freq data = today; > table year*yesno/chisq; > weight count; > run; > > > Peter > > Peter L. Flom, PhD > Statistical Consultant > www DOT peterflomconsulting DOT com > http://www.associatedcontent.com/user/582880/peter_flom.html >