Hello,
You've got a bug, Arun, the parenthesis are not right in
((1/sd1)*sqrt(2*pi)). It should be (1/(sd1*sqrt(2*pi))).
The requsted values can also be computed using ?dnorm.
d1 <- (1/(sd1*sqrt(2*pi)))*exp(-((x1-mean1)^2)/(2*(sd1^2)))
d2 <- dnorm(x1, mean = mean1, sd = sd1)
all.equal(d1, d2) # TRUE
Hope this helps,
Rui Barradas
Em 21-02-2013 02:55, arun escreveu:
Hi,
Do you need "exp^"? Should it be "exp(-((...?
x1<-as.numeric(x)
sd1<-sd(small)
mean1<- mean(small)
((1/sd1)*sqrt(2*pi))*exp(-((x1-mean1)^2)/(2*(sd1^2)))
# [1] 4.189541e-27 4.190295e-27 4.191049e-27 4.191803e-27 4.192557e-27
#[6] 4.193311e-27 4.194065e-27 4.194820e-27 4.195574e-27 4.196329e-27
#[11] 4.197084e-27 4.197839e-27 4.198594e-27 4.199349e-27 4.200105e-27
#[16] 4.200860e-27 4.201616e-27 4.202372e-27 4.203128e-27 4.203884e-27
#[21] 4.204640e-27 4.205396e-27 4.206153e-27 4.206909e-27 4.207666e-27
#[26] 4.208423e-27 4.209180e-27 4.209937e-27 4.210694e-27 4.211452e-27
#[31] 4.212209e-27 4.212967e-27 4.213725e-27 4.214483e-27 4.215241e-27
#[36] 4.215999e-27
A.K.
----- Original Message -----
From: Samantha Warnes <war...@wisc.edu>
To: r-help@r-project.org
Cc:
Sent: Wednesday, February 20, 2013 6:33 PM
Subject: [R] Fitting a gaussian distribution to a plot
I have a peak I would like to fit with a gaussian distribution, and am having
difficulties. First of all I am having difficulties getting R to except my
function input, and additionally I am having trouble plotting the non linear
model on my scatterplot of data (the peak). Here is my log:
small <-
c(507680,507670,508832,510184,511272,513380,515828,519160,525046,534046,547982,567124,590208,614506,637876,656846,669054,672976,668800,656070,637136,614342,590970,570752,554480,542882,535630,531276,528682,527682,527020,526834,526802,526860)
plot(small)
mean(small)
[1] 563996.7
sd(small)
[1] 55996.21
x <-c(0:35)
x <-as.numeric(x)
f <- ((1/(55996.21)*sqrt(2*pi)))*exp^(-((x-563996.7)^2)/(2*(55996.21^2)))
Error in exp^(-((x - 563996.7)^2)/(2 * (55996.21^2))) :
non-numeric argument to binary operator
From this point, to fit a non-linear model so I type nlm(f,507680)? I have
tried reading up on this and looking for additional information on the internet
but I am truly stuck. Thank you in advance!
Samantha
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______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
