question about ANOVA output
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question about ANOVA output
 
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Hello, everyone. I have run 2X7( two btw-subject factor ) multiple variable (subscales) ANOVA. In the table of the univariate Tests of Between-Subjects Effects, the first entry
is called Corrected Model and lists the statistics (Type II SS, DF, MS, F-test, etc) for all the DV's. What is that corrected error model? My Levine Test of equality of variance is significant for all DV's (very different cell sizes, so i am not surprised).
Does the Corrected Model have something to do with it? How should it be interpreted?
thanks so much to everyone. bozena |
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Bozena, My understanding of the Corrected Model is
this:
Brian From: SPSSX(r)
Discussion [mailto:[hidden email]] On
Behalf Of Zdaniuk, Bozena Hello, everyone. I have run 2X7( two
btw-subject factor ) multiple variable (subscales) ANOVA. In the table of the
univariate Tests of Between-Subjects Effects, the first entry is called
Corrected Model and lists the statistics (Type II SS, DF, MS, F-test, etc) for
all the DV's. What is that corrected error model? My Levine Test of equality of
variance is significant for all DV's (very different cell sizes, so i am not
surprised). Does the Corrected Model have something to do with it? How should
it be interpreted? |
Administrator
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In reply to this post by Zdaniuk, Bozena-3
The following is from one of textbook author David Howell's web-pages (http://www.uvm.edu/~dhowell/gradstat/psych341/lectures/Factorial1Folder/class4.html).
<excerpt from Howell's web-site> Diana, You asked about all of those extraneous terms in SPSS factorial anova. The "intercept" is what most textbooks (especially older ones) call the "correction factor." It is the grand total squared divided by N. (Equivalently, it is xbar squared times sqrt(N). The "Corrected total" is what everyone else calls the total sum of squares. The "total" is the total sum of squares before you subtract the correction factor, or, equivalently, sigma(X-squared). The "corrected model" is, when you have equal sample sizes, the sum of the main effects and the interaction. When you don't have equal sample sizes, it is the variability that can be explained by all three effects (the two main effects and the interaction) simultaneously. Hope that helps, Dave Howell At 1037 PM 1/26/99 -0500, Diana Sharp wrote >I am using GLM Univariate to do two factor analysis of variance for my PhD research (trying to do it without a stats coach!) The results include an "intercept", a corrected model, a total and a corrected total. Please help me understand what the intercept is. Also, the corrected model is, I assume, due to the unequal sizes of the groups in my study. Is there any way to know which one of the main effects or the interaction to attribute the "difference" between the Sum of Squares for each of the main and interaction effects versus the amount in the corrected model Sum of Squares (they never quite match up mathematically). I assume one cannot attribute it directly to any of them. >Can anyone shed some light on this for me. I would really appreciate the assistance. >In addition, thanks for the help with copying charts. I thought I was the only one seeing double. Now I can stop retyping all these (if I get your instructions to work)! >Sincerely, >Diana Sharp" </excerpt from Howell's web-site>
--
Bruce Weaver bweaver@lakeheadu.ca http://sites.google.com/a/lakeheadu.ca/bweaver/ "When all else fails, RTFM." PLEASE NOTE THE FOLLOWING: 1. My Hotmail account is not monitored regularly. To send me an e-mail, please use the address shown above. 2. The SPSSX Discussion forum on Nabble is no longer linked to the SPSSX-L listserv administered by UGA (https://listserv.uga.edu/). |
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In reply to this post by Zdaniuk, Bozena-3
Sounds like "subscale" should be a within-subjects factor, but that's just a guess based on the limited info provided. Ryan On Tue, Nov 27, 2012 at 2:34 PM, Zdaniuk, Bozena <[hidden email]> wrote:
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In reply to this post by Zdaniuk, Bozena-3
The Levine Test for equality of variance should not
care that the Ns are different. However, unequal variances do matter more when the Ns are different. Most likely, the "7 items" do not have equal variances. Is the original scaling supposed to be equal? ... If not, can this be adjusted? You might consider transformations. If it is the two groups that differ, you should consider the cause, and possibility of transformation, even more carefully. -- Rich Ulrich Date: Tue, 27 Nov 2012 19:34:50 +0000 From: [hidden email] Subject: question about ANOVA output To: [hidden email] Hello, everyone. I have run 2X7( two btw-subject factor ) multiple variable (subscales) ANOVA. In the table of the univariate Tests of Between-Subjects Effects, the first entry
is called Corrected Model and lists the statistics (Type II SS, DF, MS, F-test, etc) for all the DV's. What is that corrected error model? My Levine Test of equality of variance is significant for all DV's (very different cell sizes, so i am not surprised).
Does the Corrected Model have something to do with it? How should it be interpreted? thanks so much to everyone. bozena |
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