Thank you all for the great help. I think the optimize function and approach
solves my problem well.
Edwin Sun
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There is no "reversing the dnorm function" -- dnorm is many to one in
general (in the normal case, 2 to 1 except for the mean). How would
you "reverse" dunif, for example?!
However, with that understanding you could do a simple one dimensional
search within the range you want via optimize(), as in
Not sure if there's a pre-defined function for it, but use your basic
math skills: the normal distribution is
dnorm(x) = 1/(sqrt(2*pi)) * exp(-x^2/2),
so the inverse function (on the interval [0, infinity] is
f = function(x) {sqrt( -2*log(sqrt(2*pi) * x)) }
Since the dnorm function is not 1-to-
On Nov 12, 2010, at 5:35 PM, Edwin Sun wrote:
Hello all,
I have a question about basic statistics. Given a PDF value of
0.328161,
how can I find out the value of -0.625 in R? It is like reversing
the dnorm
function but I do not know how to do it in R.
pdf.xb <- dnorm(-0.625)
pdf.xb
Hello all,
I have a question about basic statistics. Given a PDF value of 0.328161,
how can I find out the value of -0.625 in R? It is like reversing the dnorm
function but I do not know how to do it in R.
> pdf.xb <- dnorm(-0.625)
> pdf.xb
[1] 0.328161
> qnorm(pdf.xb)
[1] -0.444997
> pno
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> -Original Message-
> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-
> project.org] On Behalf Of "Sibylle Stöckli"
> Sent: Thursday, September 23, 2010 1:43 AM
> To: r-help@r-project
On 09/23/2010 05:42 PM, "Sibylle Stöckli" wrote:
Dear R-users
Idea:
Plot a dnorm line using specific mean/sd to complete a histogram (skewed).
xs:range of y-values, ys: dnorm function
Problem:
I expected to multiply the ys function with the sample size (n=250-300). I was
wondering about a fac
Dear R-users
Idea:
Plot a dnorm line using specific mean/sd to complete a histogram (skewed).
xs:range of y-values, ys: dnorm function
Problem:
I expected to multiply the ys function with the sample size (n=250-300). I was
wondering about a factor between 12'000 and 30'000 to match the size of
On 13-Jul-10 22:21:29, Melissa Peters wrote:
> Hello,
>
> 1. I have a number of snow depth measurements (centimeters depth) that
> were acquired in a row (linear transect).
>
> A: I am trying to plot the probability density function (PDF) of these
> points. When I use the "dnorm" command and lin
Hello,
1. I have a number of snow depth measurements (centimeters depth) that were
acquired in a row (linear transect).
A: I am trying to plot the probability density function (PDF) of these points.
When I use the "dnorm" command and line type = points, the PDF is displayed
correctly. When I
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