I use this same research as an example of how proportion of variance effect sizes can be deceptive. Look at the ratios of odds or risks, or the binominal effect size display, and the picture is very different.
Cheers, [Karl L. Wuensch]<http://core.ecu.edu/psyc/wuenschk/klw.htm> From: John Kulig [mailto:[email protected]] Sent: Wednesday, February 12, 2014 7:30 PM To: Teaching in the Psychological Sciences (TIPS) Subject: Re: [tips] Scientific method: Statistical errors : Nature News & Comment Thanks Chris .. this is a terrific article and many undergrads can plow through it. I have gone back and forth on the p versus CI (which is simply rearranging the math) versus effect size issue and have come to the conclusion that we have to keep our options open and not use one rule to evaluate research findings. In my stat class - after doing my lecture on how an IQ difference of 1 point can be significantly different when N = 5000 per group - I sometimes talk about the 1988 (?) study of aspirin and Myocardial infarction in JAMA or NEJM (I am home away from my notes) which found a .8% reduction in MI from a sample of 11,000 placebo controls (risk = 1.7%) and about 11,000 who took aspirin (risk = .9%). The chi square is p < .001 but the effect size is tiny, but even that 1% drop is important when the stakes are high and you are one of the roughly 100 who was spared a MI. that's when I introduce "relative risk" thinking: .9 versus 1.7 means the chance of a MI is cut in half. That type of comparison is especially important when dealing with low base rate diseases. And thanks Jim for the divorce example ... JK ========================== John W. Kulig, Ph.D. Professor of Psychology Coordinator, Psychology 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=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=34323 or send a blank email to leave-34323-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
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