Small numerical differences can sometimes have large practical consequences. If you multiply the small reduction in risk for an individual time the population that will use the treatment, the societal impact (numbers of heart attack avoided in the entire population in a given year) can be quite large.
How many fewer people will die or have costly side effects of the flu if 80% of the population gets a shot that is 60% effective in preventing contracting the flu? _____________________________________________ Claudia J. Stanny, Ph.D. Director Center for University Teaching, Learning, and Assessment Associate Professor NSF UWF Faculty ADVANCE Scholar School of Psychological and Behavioral Sciences University of West Florida 11000 University Parkway Pensacola, FL 32514 – 5751 Phone: (850) 857-6355 (direct) or 473-7435 (CUTLA) [email protected] CUTLA Web Site: http://uwf.edu/cutla/ Personal Web Pages: http://uwf.edu/cstanny/website/index.htm On Tue, Jan 15, 2013 at 5:43 PM, Wuensch, Karl L <[email protected]> wrote: > > > > > > > That study is great for illustrating how deceptive percentage > of variance explained statistics can be. They terminated this study > prematurely because the early returns showed an effect so large (odds ratio > of about 1.8) that it was deemed unethical to continue the study. In terms > of variance explained, the treatment accounted for about one tenth of one > percent of the variance in MI.**** > > ** ** > > Cheers,**** > > [image: Karl L. Wuensch] <http://core.ecu.edu/psyc/wuenschk/klw.htm>**** > > *From:* John Kulig [mailto:[email protected]] > *Sent:* Tuesday, January 15, 2013 3:39 PM > *To:* Teaching in the Psychological Sciences (TIPS) > *Subject:* Re: [tips] Flu vaccine and p.6 level of significance**** > > ** ** > > Nice replies (Jim C, Karl W and Mike P and others ..) so I won't repeat > what has been said except to note - as a tangent to the original posts - > that in some of my classes I spend time with the "relative risk" Karl W > discusses. I use the example of aspirin and MI (heart attack) in the 1988 > (New England Journal of Med?? if I remember) article of 22,000+ physicians > who took aspirin vs. placebo. My chi square calculated on their frequencies > reveal p < .01, yet the risk of MI only drops from 1.7% to .9% in the > sample over the years studied. As an absolute value, the % decrease is very > small, but expressed as relative risk we can say we cut the risk in half. > Of course, any "significant" decrease will be championed as the stakes are > very high with MI .. and sometimes high with flu as well .. > > At any rate, I got MY flu shot! So I am OK. p < .05 :-)**** > > ========================== > John W. Kulig, Ph.D. > Professor of Psychology > Coordinator, University Honors > Plymouth State University > Plymouth NH 03264 > ==========================**** > > ** ** > > --- > > You are currently subscribed to tips as: [email protected]. > > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=13144.1572ed60024e708cf21c4c6f19e7d550&n=T&l=tips&o=23047 > > (It may be necessary to cut and paste the above URL if the line is broken) > > or send a blank email to > leave-23047-13144.1572ed60024e708cf21c4c6f19e7d...@fsulist.frostburg.edu > > > > > --- You are currently subscribed to tips as: [email protected]. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=23048 or send a blank email to leave-23048-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
<<image001.jpg>>
