[R] visualizing transition probability matrices

[Tamas Papp]

Dear List,

I have a couple of (~200) 3x3 transition probability matrices (ie each
defines a Markov chain). They are all estimated from the same
underlying process, so it ie meaningful to take their elemetwise mean
and standard deviation. [1]

First question: supposing that they are given in a list l, how do I
get their elementwise mean and standard deviation? Fortunately, the
mean of trans. prob. matrices also remains a transition probability
matrix. I'm not sure if taking the standard deviation is meaningful,
though. Any suggestions?

Second (more important): what would be the best way of visualizing the
3x3 mean and standard deviation matrices? For the mean, I thought of a
barplot where the layers add up to 1, but I have no experience with
visualization of statistical data (at least, reading this list I
learned that I should avoid circles, pie-charts and their ilk).

Thanks,

Tamas

[1] You could ask why I don't just estimate the trans. prob. matrix
just once from the whole dataset. The problem is that the process is
meant to model (real) interest rates with only three levels, and
involves many peculiar assumptions. By the way, many thanks to Kjetil
Brinchmann Halvorsen, Rolf Turner, Ted Harding, Patrick Burns and
Martin Maechler for giving detailed and helpful replies to my earlier
question about Markov chains in R.

-- 
Tamás K. Papp
E-mail: tpapp at axelero.hu (preferred, especially for large messages)
        tpapp at westel900.net
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