1. ## within subjects factors

I have two within subjects factors. One variable is fatigue (baseline, fatigue, rest). The other variable is the amplitude of swallowing muscle activity (T_tot_d when baseline, when subjects are fatigued, _tot_d after subjects rested). In my opinion, two way repeated measures MANOVA have one within-subject factor and one between-subject factor. In this case, I have two within-subjects factor groups. Is it possible for me to do MANOVA with these 2 within-subjects factors? If so, how?

2. ## Re: within subjects factors

SPSS allows you to run either MANOVA without repeated measures or repeated Measures ANOVA. In the latter you can indicate as many within-subject factors as you want.

3. ## Re: within subjects factors

Thank you so much for your response. IN my case, both the independent variable and the dependent variable are within-subjects factors. Is it still possible? I want to measure the effect of fatigue (within-subject factor) on the amplitude of swallowing muscle activity (within-subject factor).

Originally Posted by staassis
SPSS allows you to run either MANOVA without repeated measures or repeated Measures ANOVA. In the latter you can indicate as many within-subject factors as you want.

4. ## Re: within subjects factors

The dependent variable is not a factor by definition. What you seem to be having is a Repeated Measures ANOVA with 1 within-subject factor and no between-subject factors.

"Factor" in the context of ANOVA / MANOVA is a synonim of "independent variable".

Note that you are dealing with ANOVA and not MANOVA because you have only 1 dependent variable. What you need to do is open SPSS and click

Analyze -----> General Linear Model -----> Repeated Measures.

Or you can run the equivalents of this procedure in many other statistical packages.

5. ## Re: within subjects factors

Thank you so much. It is very helpful.
Do I have to test interaction between within subject factor (muscle*time)?

6. ## Re: within subjects factors

Again Muscle is the dependent variable. It is not a factor. So there is no such a thing as an interaction of Muscle with anything in the context of this ANOVA. The only factor you have is Fatigue, which is the same as Time. Since there is only 1 factor and each interaction takes at least 2 factors, there cannot be any interactions in this analysis.

7. ## Re: within subjects factors

Thank you so much for your response. It is very helpful. Is it wrong for me to put both fatigue and the amplitude of swallowing muscle activity in within-subject factor in spss? Looking forward to hearing from you.

8. ## Re: within subjects factors

Muscle is the dependent variable. It is not a factor.

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