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help > RE: Design matrix and contrast for 2x2 design
Aug 7, 2017 01:08 AM | Andrew Zalesky
RE: Design matrix and contrast for 2x2 design
Hi David, everything looks correct.
The differences between the two contrasts is that one will test whether connectivity in increased in the music/drug condition, while the other contrast will test for a decrease in connectivity in this condition. In other words, each contrast corresponds to a one-sided alternative hypothesis.
Alternatively, you can select F-test, in which case a two sided alternative hypothesis will be considered (increase or decrease). In this case, you only need to consider the contrast with a "1".
If you want to test for differences in modularity, rich club etc, you might want to consider the Brain Connectivity Toolbox (BCT). This requires some matlab expertise (BCT does not have a gui).
Andrew
Originally posted by David de Wide:
The differences between the two contrasts is that one will test whether connectivity in increased in the music/drug condition, while the other contrast will test for a decrease in connectivity in this condition. In other words, each contrast corresponds to a one-sided alternative hypothesis.
Alternatively, you can select F-test, in which case a two sided alternative hypothesis will be considered (increase or decrease). In this case, you only need to consider the contrast with a "1".
If you want to test for differences in modularity, rich club etc, you might want to consider the Brain Connectivity Toolbox (BCT). This requires some matlab expertise (BCT does not have a gui).
Andrew
Originally posted by David de Wide:
Hey Andrew,
Thank you for your quick and detailed reply.
Based on your suggestions I have contructed the 48x15 design matrix (included as attachement), contrasts and exchange blocks. As a sanity check, could you confirm that this is correct?
The contrasts for the interaction effect would be [0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 ] or [0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 ]. What is the exact difference between these two versions of the contrast?
The exhange blocks would be [1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12]
At a range of thresholds there appear to be no changes for the interaction effect with a lower p value than 0.2.
I had an additional question regarding contrasts and network analysis, given your expertise. Is there a way to look at (significant) changes in modularity, rich club coefficient or participation coefficient for the interaction of music and drug specifically?
Thank you so much for all your help.
Sincerely,
David
Thank you for your quick and detailed reply.
Based on your suggestions I have contructed the 48x15 design matrix (included as attachement), contrasts and exchange blocks. As a sanity check, could you confirm that this is correct?
The contrasts for the interaction effect would be [0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 ] or [0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 ]. What is the exact difference between these two versions of the contrast?
The exhange blocks would be [1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12]
At a range of thresholds there appear to be no changes for the interaction effect with a lower p value than 0.2.
I had an additional question regarding contrasts and network analysis, given your expertise. Is there a way to look at (significant) changes in modularity, rich club coefficient or participation coefficient for the interaction of music and drug specifically?
Thank you so much for all your help.
Sincerely,
David
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| Title | Author | Date |
|---|---|---|
| David de Wide | Aug 3, 2017 | |
| Max Kathofer | Oct 31, 2024 | |
| Andrew Zalesky | Nov 1, 2024 | |
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