PG851: GLM--ANOVA

This blog is for the use of students enrolled in either section of PG851. It is intended to be a forum for asking, discussing, clarifying, and helping.

Wednesday, March 16, 2011

Couple Questions

Posted below on other posts, but I'm not sure if they were seen:

1.) Is it okay for the hypothesis for a factorial anova to hypothesize both main and interaction effects or does that not make sense? For example, if you think both IV's will lead to a significant increase in the DV and that the highest levels of one IV with the highest levels of another IV will lead to the greatest levels of the DV, is the second an interaction effect or just two significant main effects?

2.) How do we decide if skew is "severe" enough to warrant transformation? If my skew value is -.677, should I transform it?

3.) Is a cell size ratio of 4.7 : 1 "relatively equal" such that ANOVA would be robust to it?

4.) If I write about my homogeneity of variance issues in a discussion section for this project, do I need to do the whole discussion section as I would for a real paper, or just include the one limitation?

Thank you!

posted by bfullmer @ 11:12 AM  

5 Comments:

  • At 11:20 AM, Blogger bfullmer said…

    One other I found:

    In checking section 3.03 of the APA manual, I read that "Results" should be centered, boldface, uppercase and lowercase.

    On one of my homework assignments, a grader said that if "Results" is the first heading on a page it would not be in bold? Is this correct? I don't see that in the manual.

     

  • At 12:59 PM, Blogger Brooke Yetter said…

    I went ahead and submitted my project with my best estimate as to the questions listed, but I am still curious for future reference about questions 2, 3, and the format of the heading "results" if anyone doesn't mind answering.

    Thanks for all your help!

    Brooke

     

  • At 4:55 PM, Blogger Lauren said…

    1) You should provide a hypothesis for both the main and interaction effects.

    2)If you look at the very first handout from the class, there is a slide titled Violation of the Assumption of Normality. That should give you an answer. Let me know if you have more questions.

    3)In that same handout, there is a slide titled "Homogeneity of Variance". Cell sizes are discussed here. Let me know if you have more questions about this one too.

    4)I would guess that the one limitation is fine.


    As far as the heading goes, the first heading of the page should not be bold.


    Let me know if you have more questions.

     

  • At 10:45 AM, Blogger David said…

    That last one about the headings is confusing and not explicitly described in the APA manual (as far as I can tell).

    But where this "rule" is coming from is the example report starting on page 41. There are only 3 of the headings that are not bold: Abstract, Title, References. Those are headings that would start their own pages in a full report (ie. you'd do a page break before them).

    With the results heading, it would be bold in a full report/paper. But that rule becomes confusing when you're only presenting one section.

    Hope that clarifies things.

     

  • At 8:48 AM, Blogger  said…

    There is no spirit, only body.

     

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