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Talk:Permutation test: Difference between revisions
made a note of the task specification change
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--[[User:Paddy3118|Paddy3118]] 03:22, 4 February 2011 (UTC)
:Both sets of results above appear to be incorrect. Do you believe the latter is correct, and if so, can you support it by listing statistics comparable to those above? I maintain that if you investigate it, you'll find that many of the large group of alternative means that should be exactly equal to the empirical mean are off by a little and therefore are counted among those that are greater or lesser. --[[User:Sluggo|Sluggo]] 23:43, 4 February 2011 (UTC)
:Using rational arithmetic, I get:
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:::Actually, I was asking about how the large and small value reversed (between the under and over categories) in those two cases. --[[User:Rdm|Rdm]] 17:14, 4 February 2011 (UTC)
===Using integer arithmetic ===
Rationals are a bit of overkill when the denominator is always the same. I just posted a version using all integer arithmetic. The problem with floats is those 313 cases where the differences are equal. Anything that causes the difference to be off by the tiniest bit can cause them to be mis-categorized. I don't know enough statistics to know how this is typically handled. For this task, it might be enough to change the task description to provide experimental results as an integer score from 0 to 100. While we're at it, we could change the task to specify that the difference is treatment-control. That would eliminate the double solution.—[[User:Sonia|Sonia]] 20:12, 4 February 2011 (UTC)
:I'm in favor of amending the task as you recommend, and I'll do it if no one objects in the next few days or does it first. --[[User:Sluggo|Sluggo]] 23:46, 4 February 2011 (UTC)
== Name of task ==
Shouldn't this be all combinations instead of all permutations? What difference does the order of members within the control or treatment group make (other than extra computation time)? --[[User:Rdm|Rdm]] 16:08, 1 February 2011 (UTC)
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: "Permutation test" is the conventional name for this test according to the Wikipedia, even though it may be a misnomer. --[[User:Sluggo|Sluggo]] 02:24, 4 February 2011 (UTC)
== Change in specification ==
In keeping with the developing consensus of opinion, I have changed the task specification to use integer test data, and specified that the difference in means is to be calculated by subtracting the control group mean from the treatment group mean. The correct results should be <math>12.80%</math> and <math>87.20%</math>. --[[User:Sluggo|Sluggo]] 21:05, 10 February 2011 (UTC)
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