|Date: ||Fri, 7 Apr 2006 16:06:35 -0600|
|Reply-To: ||Matthew Pirritano <email@example.com>|
|Sender: ||"SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>|
|From: ||Matthew Pirritano <firstname.lastname@example.org>|
|Subject: ||Re: Logistic Regression|
|Content-Type: ||text/plain; charset=UTF-8; format=flowed|
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.
Matthew Pirritano, Ph.D.
National Science Foundation Post-Doctoral Fellow
College of Education
Department of Individual, Family & Community Education
1 University of New Mexico
Albuquerque, NM 87131-0001
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.
> 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.
>> 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