As Gerd Gigerenzer once said: we need more statistical thinking and fewer statistical rituals. Chris ....... Christopher D Green Department of Psychology York University Toronto, ON M6C 1G4
[email protected] http://www.yorku.ca/christo > On Feb 12, 2014, at 7:30 PM, John Kulig <[email protected]> wrote: > > > > > > > > > > > > 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 > ========================== > > From: "Jim Clark" <[email protected]> > To: "Teaching in the Psychological Sciences (TIPS)" > <[email protected]> > Sent: Wednesday, February 12, 2014 6:46:59 PM > Subject: RE: [tips] Scientific method: Statistical errors : Nature News & > Comment > > Hi > > Interesting article, although I need to think more about it. One obvious > weakness is the old canard about effect size being a better indicator of > importance than p value. The author uses the example of a divorce rate > change being tiny: "meeting online nudged the divorce rate from 7.67% down to > 5.96%." One source indicates that there are about 2,000,000 marriages in the > USA per year. 7.67% is 153,400 divorces, 5.96% is 119,200 divorces, for a > reduction of 34,200 divorces or 22.3% fewer divorces every year. Not exactly > what I would call a "tiny" difference. > > Take care > Jim > > Jim Clark > Professor & Chair of Psychology > 204-786-9757 > 4L41A > > > -----Original Message----- > From: Christopher Green [mailto:[email protected]] > Sent: Wednesday, February 12, 2014 4:43 PM > To: Teaching in the Psychological Sciences (TIPS) > Subject: [tips] Scientific method: Statistical errors : Nature News & Comment > > An interesting article about the problems of p-values that might even be > understandable to undergraduates. > http://www.nature.com/news/scientific-method-statistical-errors-1.14700 > > Chris > ....... > Christopher D Green > Department of Psychology > York University > Toronto, ON M6C 1G4 > > [email protected] > http://www.yorku.ca/christo > --- > You are currently subscribed to tips as: [email protected]. > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=13251.645f86b5cec4da0a56ffea7a891720c9&n=T&l=tips&o=34162 > or send a blank email to > leave-34162-13251.645f86b5cec4da0a56ffea7a89172...@fsulist.frostburg.edu > > --- > You are currently subscribed to tips as: [email protected]. > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=13338.f659d005276678c0696b7f6beda66454&n=T&l=tips&o=34164 > or send a blank email to > leave-34164-13338.f659d005276678c0696b7f6beda66...@fsulist.frostburg.edu > > > --- > > You are currently subscribed to tips as: [email protected]. > > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=430248.781165b5ef80a3cd2b14721caf62bd92&n=T&l=tips&o=34165 > > (It may be necessary to cut and paste the above URL if the line is broken) > > or send a blank email to > leave-34165-430248.781165b5ef80a3cd2b14721caf62b...@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=34176 or send a blank email to leave-34176-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
