[EMAIL PROTECTED] wrote: > > > what is the rationale for the .05 and .01 level of signifance as > acceptable? who came up with this Eurocentric concept anyway? "The rapidity with which the probability falls off as the deviation increases is well shown in these tables. A deviation exceeding the standard deviation occurs about once in three trials. Twice the standard deviation is exceeded only about once in 22 trials, thrice the standard deviation only once in 370 trials, while Table II. shows that to exceed the standard deviation sixfold would need nearly a thousand million trials. The value for which P =ยจ.05, or 1 in 20, is 1.96 or nearly 2 ; it is convenient to take this point as a limit in judging whether a deviation is to be considered significant or not. Deviations exceeding twice the standard deviation are thus formally regarded as significant. Using this criterion, we should be led to follow up a negative result only once in 22 trials, even if the statistics are the only guide available. Small effects would still escape notice if the data were insufficiently numerous to bring them out, hut no lowering of the standard of significance would meet this difficulty."
*Fisher, Ronald A.* (1925). /Statistical methods for research workers/ <http://psychclassics.yorku.ca/Fisher/Methods/>. Originally published in London by Oliver and Boyd. (pp. 46-47). > And how about single-case studies? What about them? Regards, Chris -- Christopher D. Green Department of Psychology York University Toronto, ON M3J 1P3 Canada 416-736-2100 ex. 66164 [EMAIL PROTECTED] http://www.yorku.ca/christo/ "Part of respecting another person is taking the time to criticise his or her views." - Melissa Lane, in a /Guardian/ obituary for philosopher Peter Lipton ================================= --- To make changes to your subscription contact: Bill Southerly ([EMAIL PROTECTED])
