Re: [R] variance of discrete uniform distribution

On Mon, Mar 8, 2010 at 3:44 PM, casperyc wrote: > > Hi Rolf Turner , > > God, it directed to the wrong page. > > I firstly find the formula in wiki, than tried to verify the answer in R, > now, given that 143/12 ((n^2-1)/12 ) is the correct answer for a discrete > uniform random variable, > I am s

Re: [R] limit to p-value using t.test()

On Sat, Feb 6, 2010 at 8:53 AM, Pete Shepard wrote: > I am using t-test to check if the difference between two populations is > significant. I have a large N=20,000, 10,000 in each population. I compare a > few different populations with each other and though I get different t-scores, > I get the

Re: [R] R on amazon's EC2 "cloud"?

On Sun, Dec 27, 2009 at 3:33 PM, Carlos J. Gil Bellosta < c...@datanalytics.com> wrote: > I tried Amazon EC2 with R recently and wrote an entry about it to a blog I > collaborate with: > > http://analisisydecision.es/probando-r-sobre-el-ec2-de-amazon/ > > (Unfortunately, it is in Spanish...) > Go

Re: [R] [ how can sample from f(x)~x^(a-1)

On Fri, Dec 25, 2009 at 8:07 AM, wrote: > Hello all > how can sample from f(x)~x^(a-1)*ind(0,min(b,-log(u)) in R? > where a and b is positive constand and 0 If the idea is that X is a random variable, then you need to decide what kind of random variable it is. For example, if you wanted to as

Re: [R] regex question

Here's what I came up with: > gsub("(\\w)[^ ]+[\\b ]", "\\1", astr) [1] "Timtowtdit" You might be interested in Regular Expressions Cookbook from O'Reilly (publisher not author) or http://www.regular-expressions.info/ I usually bumble along knowing there are better ways to do whatever I am doing

[R] Hmisc summarize() with level "" in by variable

I was using summarize() in a data set in which one of the levels of the by variable was "". The summary statistic was consistently off by one level and the "" level was not in the output data frame. I tried to report it as a bug, but I could not log into the Hmisc bug reporting website to do so.

[R] latex(Hmisc): cgroup + rownames shifts column names

I have submitted this as a bug (http://biostat.mc.vanderbilt.edu/trac/Hmisc/ticket/29) but I am wondering if anyone else has seen it or perhaps developed a workaround. I could certainly fix the LaTeX by hand, but I am using this inside Sweave, so it is a bit cumbersome. The exact same code used t