tag:blogger.com,1999:blog-4195821979314289036.post5802357226097568026..comments2011-01-08T06:44:26.229-08:00Comments on A Math Teacher In Training: Psigh... A Response to Daryl Bem's Work Regarding the Existence of PsiBruce Launeyhttp://www.blogger.com/profile/07535658515228032247noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-4195821979314289036.post-89069644290758509252011-01-08T06:44:26.229-08:002011-01-08T06:44:26.229-08:00You could probably get something more realistic th...You could probably get something more realistic than your uniform random from 0 to 24 by using a random binomial instead: in other words, assume that they have a fixed probability p of recalling each of the 24 words in each case. This assumes the recollections are independent, which is a bit unrealistic of course, but not as unrealistic as the uniform distribution. It's probably also easier to assume that all the subjects have the same p, but you could also code some variation in there if you wanted to. <br /><br />Excel doesn't have a random binomial function, apparently, but you can make a list of 24 random numbers and count how many of them are less than p easily enough.Joshua Zuckerhttp://www.blogger.com/profile/04689961247338617418noreply@blogger.comtag:blogger.com,1999:blog-4195821979314289036.post-82836658869835441492010-12-11T06:41:23.827-08:002010-12-11T06:41:23.827-08:00Aidey is absolutely right about the effect of the ...Aidey is absolutely right about the effect of the range of possible values on the variance of the distribution. I have begun to revise the assumed range of possible values to see what effect it would have on the resulting DR% values that Bem generated. The narrower the possible range of values, the smaller the variance, and the smaller the average DR%. I would be interested to see how many words the participants in Bem's study actually recalled to see what assumed values for my randomized approach would be valid. I could then rerun my randomized analysis to see how it compares to Bem's results when the bounds are more accurate.<br /><br />Thanks Aidey! I appreciate your insight. I'm a little embarassed that I didn't think about the fact that my assumptions would impact the variance as significantly as it did.Bruce Launeyhttp://www.blogger.com/profile/07535658515228032247noreply@blogger.comtag:blogger.com,1999:blog-4195821979314289036.post-48510454371094357612010-12-11T05:09:45.826-08:002010-12-11T05:09:45.826-08:00Your assumptions about the bounds of the random fu...Your assumptions about the bounds of the random function do in fact bias your results. Bem used the t-distribution, which is bell-shaped. Your random function results in a large variance, which is to say that your bell shape is wide, so finding a result greater than 2.27 is not so unusual. If the bell is narrower (i.e., lower variance), then the same result will be more unlikely. This is bad news for the "common sense" view of the world - maybe the future can affect the present after all!aideyhttp://aidey.wordpress.com/noreply@blogger.com