Hi Senthil,

Please, see below:

On 10 June 2016 at 14:21, Senthil Kumaran <[log in to unmask]> wrote:

Dear Dr. Anderson,

Thanks for creating some awareness, and the design.
As you suggested, we will disregard the healthy adult population.

How are the random values generated? Can you throw some light on that?

You mean, the random values in the spreadsheet? These are simply (literally) random values, produced with the function RAND(), that's all. They are here just to illustrate, and you'd replace these for the actual values of your continuous variable, i.e., the cognitive scores.

Why EB is not including all the subjects?

Sorry, my mistake in not filling all to the end. All subjects go in the same big EB, which therefore can be ignored.

Our sample size is:
Group 1: Healthy Children (age matched with patient population): Baseline: n=6,
Group 2: Control Patient group (Non-therapy): Baseline: n=11,
Group 3: Experimental Patient Group (therapy): Baseline: n=13
Group 1: Follow-up: n=2 (we have not included in the analysis since the number is low; can we include?)
Group 2: Follow-up: n = 8
Group 3: Follow-up: n = 6
How we interpret difference between A>B (F1) and cogA>cogB (F2)

Ugh, so this is a repeated measures design? Then forget it all, need a different design and the hypotheses are likely different too.

Also, once the design is executed, how to extract the FA values?

I think before running anything I'd recommend that you discussed with the main investigator of this project what exactly the hypotheses were, if there is a strategy in place to deal with missing data.

Also, it is crucial that you gain some familiarity with imaging analysis and with FSL tools so as to know what to ask. An excellent starting point is this book, and also Jeanette Mumford group on Facebook and her Youtube channel. Andy Jahn has also a good blog full of information to start. Consider especially also doing the FSL tutorial in your computer (slides and datasets are available here).

All the best,

Anderson

With warm regards

Senthil