Repeated Measures ANOVA Question

[MdmeBtrfly]

Hi All,

I've done a Repeated Measures ANOVA assessing mood during different kinds of weather. 5 subjects were asked to rate their mood on a cloudy day and then on a sunny day. I found a significant within-subjects effect of weather. My problem lies here....

Next step, I'm asked to think about how sure I can be of my results. I do understand that in within-subjects designs you should be concerned about contamination of results by spillover, but I'm thinking that it's too simplistic just to say that for this problem. Any ideas of what potential flaws are in this particular example? Thanks so much!

 

[JohnM]

If you're asked how you can be sure of your results, I don't think listing potential flaws will answer the question.

Write out the potential flaws in any repeated-measures design, then explain what you did in your particular design to avoid or minimize those potential pitfalls.

i.e., were some of the participants asked on a sunny day first, then a rainy day, and others the opposite - rainy day first, then sunny?.....or was the sequential experience the same for all participants?

there's potential for spillover / carryover effects if all participants follow the same sequence....

 

[MdmeBtrfly]

Thanks so much for your response! This is hypothetical data, and yes, all the participants followed the same sequence. I so guess that the mood they had on a cloudy day could have residual effects on the mood they report for the sunny day. I suppose that's all I could really say, because no more information has been provided to us in class.