Message-ID: <x2n16x6338.fsf@blueberry.kubism.ku.dk>
Date: 2001-06-24T20:21:47Z
From: Peter Dalgaard
Subject: graphing the normal distribution
In-Reply-To: David White's message of "Sun, 24 Jun 2001 15:25:24 -0400 (EDT)"
David White <dwhite at ling.ohio-state.edu> writes:
> Hello,
>
> I'd like to make some simple example graphs of the normal distribution,
> varying standard deviation, mean, and kurtosis across examples.
>
> I have been able to manipulate mean and sd using rnorm and hist:
> y_hist(rnorm(1000000, mean=100, sd=50), 50, plot=F)
> plot(y$mid,y$count,type="l")
>
> Two questions:
>
> 1) n=100000 seems like a lot of samples to approach a smooth
> curve. Is there a way to make the curve smooth, but computationally less
> demanding?
Perhaps
curve(dnorm(x,mean=0,sd=1),from=-3,to=3)
etc.?
> 2) What can I do to change the "peakiness" of the distribution?
Nothing within the Normal distribution family since it has constant
shape... the t-distributions have bigger kurtosis for given variance
as far as I recall, and uniform distributions have less. (Don't shoot
me if I got that wrong, it's not like I need to use it every day.)
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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