These are item analyses so the DV is whether they got the item right or wrong (0,1). Each treatment was given to different subjects. I think that we have a 2 X 2 X 2 factorial design (Sound by Picture by ELL status) with different subjects in each cell.

Thanks Matt

Matthew Pirritano, Ph.D. National Science Foundation Post-Doctoral Fellow College of Education Department of Individual, Family & Community Education MSC05 3040 1 University of New Mexico Albuquerque, NM 87131-0001 Telephone (505)277-7115 FAX (505)277-8361

Art Kendall wrote: > What is/are your dependent variable(s)? > > Do you still have access to enough subjects to try a full factorial > design i.e.., 2**4 design.? > Was each treatment given to a separate group of subjects, or were the > same subjects given all of the treatments. > > > Art > Art@DrKendall.org > Social Research Consultants > > > Matthew Pirritano wrote: > >> Hello all, >> >> We've conducted a study where we've tested the effects of including >> narration and pictures with math items. The narration is simply a voice >> reading aloud the problem. There were four conditions (Text Only, >> Picture and Text, Picture and Narration, Sound and Text). We divided >> our analyses into two main conditions, Picture (with picture, without >> picture), and Sound (with narration, without narration). I've run >> logistic regressions (LR) looking to see if the effects of our >> conditions varied with language groups (ELL or non-ELL), while >> controlling for overall performance on all of the problems (11 >> problems). I was originally told to run the logistic regressions >> including either the Picture variable, OR the Sound variable. I did >> this. But it occurred to me that by only including one of these >> variables at a time I was ignoring the fact that a problem could have >> had both Picture and Sound present or neither present. Should I have >> included Picture and Sound in the LR simultaneously? And because I'm >> interested in the interaction between condition and language group is it >> okay to run one set of analyses where I include the interaction between >> picture and language group, and another including the interaction >> between sound and language group? My reasoning for the two sets of >> analyses is that if I included both interactions at the same time the >> results would not be very interpretable. >> >> As always, any help much appreciated. >> >> thanks >> Matt >> >> Matthew Pirritano, Ph.D. >> National Science Foundation Post-Doctoral Fellow >> College of Education >> Department of Individual, Family & Community Education >> MSC05 3040 >> 1 University of New Mexico >> Albuquerque, NM 87131-0001 >> Telephone (505)277-7115 >> FAX (505)277-8361 >> >>