Since trials with latencies greater than 10.000ms are to be discarded according to Greenwald et al.'s "improved scoring algorithm", N1 and N2 aren't necessarily equal.
Exponentiation, more commonly denoted as a^n.
~Dave
Thanks for your quick answer. OK I found something in the stuff you told me for inspection. This is kind of a manual how to calculate the D-Score.
COMPUTE Numerator_for_D = (Mn2 - Mn1) .
COMPUTE Denominator_for_D = SQRT( ( ((N1-1) * SD1**2 + (N2-1) * SD2**2)
+ ((N1+N2) * ((Mn2-Mn1)**2) / 4) ) / (N1 + N2 - 1) ) .
COMPUTE D = Numerator_for_D / Denominator_for_D .
And I also don't understand what the double **means...
I calculated an IAT Score by just using the mean difference over subjects between the two blocks...
Can somebody tell me how I can calculate the D-Score out of it? What exactly is the advantage of the D-Score in contrast to the plain difference between the two blocks?
All of this is discussed at length in Greenwald et al. (2003), available here: http://faculty.washington.edu/agg/pdf/GN&B.JPSP.2003.pdf. Additionally, SPSS syntax for computing D-scores from data gathered with IAT Inquisit templates is available from the IAT download page: http://www.millisecond.com/download/samples/v3/IAT/default.aspx.
The appropriate correlation coefficient would depend on a number of factors (design, scale level, etc.). Pearson's r should be okay to use in most cases. However, I suggest you look through the available research literature, find a similar case to yours and check what was used there.
Hey there,
I have a question about Scoring the IAT. I have an finished SPSS File with the IAT Reactionstime (One Line Per Subject) with the variables compatibleblock and incopatibleblock...
Can you also tell me which correlation coefficient you use for correlations with explicit measures?
Thanks a lot