## how to calculate d'?

Hi,
I'm doing an AX discrimination task for my dissertation. I've tested 36 subjects on the discrimination of segment duration. I'm using a continuum of 3 durations for each segment and thus I have 9 pairings (which i'm calling 'conditions') for each segment, 3 of which are the same and 6 of which are different (i.e. 1_1, 1_2, 1_3, 2_1, 2_2, 2_3, 3_1, 3_2, 3_3).

For discrimination data, the literature reports d' scores both for subjects across stimuli and for each condition across subjects.

I understand how to calculate a d' score for each participant across conditions since you have data for hits, misses, false alarms, and correct rejections, but I don't understand how to calculate it for each of my 9 conditions (across subjects). How is it possible to calculate d' when for the 'same' conditions you only have data for false alarms and correct rejections and for the 'different' conditions you only have data for hits and misses????? I just don't get it...

I'm sure this is a really stupid question and I hope it even makes sense, but I'm a bit of a stats newbie! forgive me!