[R] 95% CI of a IQR and more
dwinsemius at comcast.net
Sun Dec 12 19:11:17 CET 2010
On Dec 12, 2010, at 10:13 AM, Beckie wrote:
> Hi guys!
> I have to calculate the 95% CI for the IQR. I have 100samples with
> continuous numbers using a compute-intensive method.
> 1)I can calculate the 95%CI and the IQR, but I don't know how to
> the CI of the IQR, does anybody have any idea, which method will be
You could bootstrap the distribution of the 25th and 75th order
statistics in your sample or you could look up the analytical
distribution in David's "Order Statistics". I can assure you that the
first option will be easier. Come to think of it that would not
actually answer the question, but it should point you to a particular
class of tools.
> 2)I have a 2x2 table with gender vs blue eyes or not.
Making this sound even very much more like homework. (HW not generally
encouraged on R-help. Suggest you read the Posting Guide.)
> How do I calculate the
> expected two-by-two contingency tables? Do I assume that half the
> people are
> female and half are males. And assume some random chance of your
> being blue?
Doesn't sound right to me. You might want to look at the documentation
and code for fisher.test().
> 3) I have to use a permutation test, to calculate whether there is a
> difference in the median of two samples. - How do I do that? I thought
> permutation test only was for categorical data?
Check out the coin package.
David Winsemius, MD
West Hartford, CT
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