similar to: Curious Behavior with Curve() and dnorm()

#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) ,

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]

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 change the line type = line, it displays the PDF curve with numerous lines connecting multiple

I'm trying to provide different parameters to the integrate function for various probability functions. I'm using dnorm as the simplest example here. For instance integrate(dnorm, -1.96, 1.96) produces the correct answer for a normal distribution with mean 0 and standard deviation 1. I've tried two ways to use mean=2.0 and standard deviation 1, but with no luck. The examples follow.

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,

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

Hi all, I've got this graphics question which really should be easy. I want to shade an area between bounds under a curve. A suitable beginning seems to be the following: > plot(dnorm,-4,4) > segments(-4,0,4,0) > segments(-2,0,-2,dnorm(-2)) > segments(2,0,2,dnorm(2)) It is the area between -2 and 2 which I want to shade (or something similar). Hints anyone? Robert

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 -- View this message in context:

Hello, ? What I really want to do is to add a rejection region in the form of a long rectangle to a density plot I have drawn.? I am getting? 2 plots.? How can I add rectangle to first plot?? see code below. First section works fine.? It just is not quite what I want. # NORMAL DISTRIBUTION PLOT OF RAW DATA WITH UPPER CRITICAL LEVEL - ok xcrit=144.1 # *** single-sample Upper one-tailed

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 [[alternative HTML version deleted]]

Hi Abou, Try this: library(plotrix) curve(rescale(dnorm(x ,mean=mean(Lizard.tail.lengths),sd=sd(Lizard.tail.lengths)), c(0,6)),add=TRUE, col=2, lwd = 2) Jim On Mon, Sep 25, 2017 at 9:35 AM, AbouEl-Makarim Aboueissa <abouelmakarim1962 at gmail.com> wrote: > Dear All: > > One more thing. > > I want to add the normal curve to the histogram. Is there away to stretch > the

Hi List, I would like to plot multiple curves (parametric density curves) in one plot. For example: # parameters for three normal density curves parms = data.frame(ID=c(1,2,3),mu=c(50,55,60),sigma=c(10,12,15)) # I can easily draw three normal density curves using curve(): curve(dnorm(x,mean=parms$mu[1],sd=parms$sigma[1]),from=0, to=150, ylab="density", col="red")

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.

Hi, I am facing the problem that I want to plot a histogram chart set freq to true and overlay with normal or weibull or exponential distribution curve. The sample code is shown as below: >samp<-c(-8.2262,-8.2262,-8.2262,-8.20209,-8.09294,-8.07321,-8.07321, -8.07321,-8.07175,-8.04948,-8.04948,-8.04948,-8.03848,-8.03848,

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

Hi I have created the following plot over the empirical returns.. What I now want to do is to overlay a curve/line with the normal density as a comparison of the two. Does anyone know how to do this? (NB the last two lines are the problem, and are wrong, I know). Thank you in advance! Rikke http://r.789695.n4.nabble.com/file/n3768783/S%26P_500_spot_and_return_2010.csv

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! [[alternative HTML version deleted]]

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;

Dear All: One more thing. I want to add the normal curve to the histogram. Is there away to stretch the peak of the curve to the top of the histogram or at least near to the top of the histogram. Please see the code below. Lizard.tail.lengths <- c(6.2, 6.6, 7.1, 7.4, 7.6, 7.9, 8, 8.3, 8.4, 8.5, 8.6,8.8, 8.8, 9.1, 9.2, 9.4, 9.4, 9.7, 9.9, 10.2, 10.4, 10.8,11.3, 11.9) x<-seq(5,12, 0.001)

Dear List, When I plot a histogram with 'freq=FALSE' and overlay the histogram with a normal pdf curve, everything looks as expected, as follows: x <- rnorm(1000) hist(x, freq=FALSE) curve(dnorm(x), add=TRUE, col="blue") What do I need to do if I want to show the frequencies (freq=TRUE) with the same normal pdf overlay, so that the plot would still look the same? Regards,