Displaying 20 results from an estimated 10000 matches similar to: "Integrate(dnorm) with different mean and standard deviation help"
2011 Sep 24
1
Help with Integration Output
Hi,
I need to do a calculation in R which involves adding the estimate of a
numerical integration with another number - however, if I add the number to
the output of the intergrate function (which when run on its own provides me
with a number with error), I get the message 'non-numeric argument to binary
operator'. How would I be able to avoid this and use the estimate?
eg: I have the
2006 Feb 10
3
Accuracy of dnorm (PR#8586)
Full_Name: Marco Vezzoli
Version: 2.2.0 2.1.0 2.0.0
OS: Solaris, Windows, Linux
Submission from: (NULL) (57.78.11.38)
The dnorm functions yield a wrong value when the standard deviation is near to
1e-1
e.g.
> dnorm(0,mean=0.04,sd=0.3)
[1] 1.318039
this error is consistent in various version and os.
2006 Jan 20
2
big difference in estimate between dmvnorm and dnorm, how come?
Dear R community,
I was trying to estimate density at point zero of a multivariate
distribution (9 dimensions) and for this I was using a multinormal
approximation and the function dmvnorm , gtools package.
To have a sense of the error I tried to look the mismatch between a
unidimensional version of my distribution and estimate density at
point zero with function density, dmvnorm and dnorm.
At
2005 Feb 10
2
Curious Behavior with Curve() and dnorm()
I am attempting to wrap the histogram function in my own custom
function, so that I can quickly generate some standard plots.
A part of what I want to do is to draw a normal curve over the histogram:
> x <- rnorm(1000)
> hist(x, freq=F)
> curve(dnorm(x), lty=3, add=T)
(for normal use, x would be a vector of empirical values, but the
rnorm() function works for testing)
That
2010 Dec 06
3
0.5 != integrate(dnorm,0,20000) = 0
Hello:
The example "integrate(dnorm,0,20000)" says it "fails on many
systems". I just got 0 from it, when I should have gotten either an
error or something close to 0.5. I got this with R 2.12.0 under both
Windows Vista_x64 and Linux (Fedora 13); see the results from Windows
below. I thought you might want to know.
Thanks for all your work in creating
2000 Nov 07
3
infinity in integrate function in R
sorry the integration was from -Inf to 1.96
The integrate function in R is not taking Inf (infinity). How do you use
infinity in R. I was doing: integrate(dnorm,- Inf, 1.96) and I was getting
Error: NA/NaN/Inf in foreign function call (arg 2). Obviously this should
be equal to pnorm(1.96)= 0.9750021. How do you get around the infinity
problem in R?
2003 Oct 31
4
dnorm() lead to a probability >1
Howdee,
One of my student spotted something I can't explain: a probability >1 vs a
normal probability density function.
> dnorm(x=1, mean=1, sd=0.4)
[1] 0.9973557
> dnorm(x=1, mean=1, sd=0.39)
[1] 1.022929
> dnorm(x=1, mean=1, sd=0.3)
[1] 1.329808
> dnorm(x=1, mean=1, sd=0.1)
[1] 3.989423
> dnorm(x=1, mean=1, sd=0.01)
[1] 39.89423
> dnorm(x=1, mean=1, sd=0.001)
[1]
2008 Jul 08
1
odd dnorm behaviour (?)
#Quick one hopefully. Shouldn't dnorm be returning the pdf? Last time
I checked,
#a probability shouldn't be greater than 1 as produced by:
curve(dnorm(x,0,.1),from=-1,to=t)
#Shouldn't I be getting an axis more like that produced by:
f=function(x,m,s){
y=rep(NA,length(x))
for(i in 1:length(x)){
y[i]=integrate(
dnorm
, upper=x[i]+sqrt(.Machine$double.eps)
,
2010 Sep 23
2
dnorm
Dear R-users
Idea:
Plot a dnorm line using specific mean/sd to complete a histogram (skewed). xs:range of y-values, ys: dnorm function
Problem:
I expected to multiply the ys function with the sample size (n=250-300). I was wondering about a factor between 12'000 and 30'000 to match the size of the dnorm line with the specific histogram.
Thanks
Sibylle
hist(Biotree[Ld,]$Height2008,
2010 Nov 12
4
dnorm and qnorm
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
> pnorm(pdf.xb)
[1] 0.628605
Many thanks,
Edwin
--
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2006 Sep 27
3
t-stat Curve
Number of subjects = 25
Mean of Sample = 77
Standard Deviation (s) = 12
sem = 2.4
df = 24
The claim is that population mean is less than 80
* > 80
So our H0 (null hupotheis) is * > 80
> qt(.95,24)
[1] 1.710882
> qt(0.05, 24)
[1] -1.710882
tstat = -1.25 on t24 falls between 1.711 (.95,24) and *1.711 (.005,24)
How Could I sketch t curve for the above data where my * would be at the
2007 Feb 26
3
returns from dnorm and dmvnorm
Hi All,
Why would calls to dnorm and dmvnorm return values that are above 1? For
example,
> dnorm(0.00003,mean=0, sd=0.1)
[1] 3.989423
This is happening on two different installations of R that I have.
Thank you.
Hailu
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2011 Oct 23
1
how to plot a distribution of mean and standard deviation
Hi,
I have the following data about courses (504) in a university, two
attributes about the proportion of resources used (#resources_used /
#resources_available), namely the average and the standard deviation.
Thus I have:
[1] n=504 rows
[2] 1 id column and 2 attributes
Here's a sample of the data:
courseid,average,std
12741,1,0
17161,1,0
12514,1,0
2010 Jan 13
1
Formula for normal distribution with know mean and standard error and n terms
Hello,
I am searching for a method to calculate a normal distribution.
For example this equation is used to calculate the normal curve when the
mean and standard deviation are know.
p(x) = (1/?*sqrt(2?)) x exp (- (x-?)2/2?2)
or
(Embedded image moved to file: pic27350.jpg)Normal Probability Distribution
Formula
However, some of the literature I'm reading (I'm building an ecological
2006 Jul 14
3
Generating random normal distribution with mean 0 and standard deviation 1
Hello,
This must be really simple, but I can't find it on R Site search. I need to
generate a random normally distributed series with mean 0 and sd 1. In
Matlab, this code is randn(n).
The closest I found is runif(20,-1,1) but this forces a maximum and a
minimum, and there's no way to specify a standard deviation of 1.
>sd(runif(20,-1,1))
[1] 0.578164
2019 Dec 07
2
What should dnorm(0, 0, -Inf) return?
Hi,
Apropos of a recent Inf question, I've previously wondered if dnorm "does the right thing" with
dnorm(0, 0, -Inf)
which gives zero. Should that be zero or NaN (or NA)?
The help says "'sd < 0' is an error and returns 'NaN'" and since -Inf < 0 is TRUE, then... is this a bug?
Thank you,
Stephen
Rochester, MN USA
2011 Feb 08
3
Perform one-way ANOVA using standard deviation and mean
Hi! I need to perform ANOVA on a couple of data sets. The only information I have are N, Mean and Standard deviation. I am very new to R, so can someone point me to the right direction on where to go? Thank you very much.
Sincerely
Niny Rao, PhD
Philadelphia University
2010 Feb 10
1
Integral of function of dnorm
Dear all,
How is it possible in R to calculate the following integral:
Integral(-Inf, Inf)[log(dnorm(mean = 3, sd = 1))]
how can I define that the density dnorm is taken on (-Inf, Inf)
Thanks a lot!
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2019 Dec 08
2
What should dnorm(0, 0, -Inf) return?
Yes, that looks like a bug and an easily fixable one too.
However, I spy another issue: Why do we check the !R_FINITE(x) && mu == x before checking for sd < 0 ? The difference is whether we
return ML_NAN;
or
ML_ERR_return_NAN;
but surely negative sd should always be an error?
I'd be inclined to do
if (sigma < 0) ML_ERR_return_NAN;
if(!R_FINITE(sigma)) return R_D__0;
2010 Aug 25
1
Estimate average standard deviation of mean of two dependent groups
Dear R-experts!
I am currently running a meta-analysis with the help of the great metafor
package. However I have some difficulties setting up my raw data to enter it
to the meta-analysis models.
I have a group of subjects that have been measured in two continuous
variables (A & B). I have the information about the mean of the two
variables, the group size (n) and the standard deviations of