Modules for multitesting

[Claybarn]

Added modules for multiple hypothesis testing and stratified multiple hypothesis testing.

Would be great to get a second pair of eyes on this and make sure everything checks out!

[akglazer]

Hi Clayton, thanks so much for this! It looks like a potentially very useful contribution. Could you add some more comments to your code and a few unit tests so we can better evaluate it?

[Claybarn]

Hey Amanda, done!

I noticed what I thought was strange behavior in the stratified module. On line 130 the number of groups is used to decide whether to use mean or std as the statistic. However I believe this should be the number of conditions. I made this change for the multitest_stratified module, but if I am mistaken I can change it back to groups.

I also had the thought it would be more parsimonious to fold the multitest modules into the core and stratified modules, as the desired behavior of the multitest modules with a single test is identical to the original modules. But open to whatever!

[Claybarn]

@akglazer Did you get a chance to look over the tests?

[akglazer]

Hi Clayton! So sorry for the delay on this and thanks so much for all your work! What method are you implementing in this code? It looks like Westfall-Young maxT?

[Claybarn]

No worries! Yes this is the Westfall-Young method. If I have time in the next few weeks I will speed things up by implementing the Numba library which has worked beautifully for me in the past.

[akglazer]

Thanks so much! We really appreciate the time you've put into this and for reminding us of the need for multiple testing corrections. We've been working on implementing Westfall-Young, along with other corrections, and think ultimately it will be better integrated in npc.py so we can leverage the Experiment class and minimize code duplication.

[Claybarn]

I failed to notice npc and the experiment class! Makes sense. Removed the Westfall-Young method in this PR and updated the tests accordingly.

[Claybarn]

Hey @akglazer, any chance of merging this soon?

[akglazer]

Hi Clayton, we are planning to add multiple testing functionality soon, we are just working out some changes to the code structure still.