Displaying 20 results from an estimated 1000 matches similar to: "how to create normal qqplot with the 95% confidence interval"
2009 Nov 02
7
qqplot
Hi,
We could use qqplot to see how two distributions are different from each other. To show better how they are different (departs from the straight line), how is it possible to plot the straight line that goes through them? I am looking for some thing like qqline for qqnorm. I thought of abline but how to determine the slope and intercept?
Best wishes,
Carol
2010 Jun 24
4
Simple qqplot question
I am a beginner in R, so please don't step on me if this is too
simple. I have two data sets datax and datay for which I created a
qqplot
qqplot(datax,datay)
but now I want a line that indicates the perfect match so that I can
see how much the plot diverts from the ideal. This ideal however is
not normal, so I think qqnorm and qqline cannot be applied.
Perhaps you can help?
Ralf
2006 Oct 25
1
Drawing a reference line for a qqplot with reference to Weibull distribution
Hi,
I'm trying to create a qqplot with reference to a Weibull distribution
including a reference line. This is my current code:
lights.data <- scan("lights.dat")
#Generate Weibull quantiles
prob.grid <- ppoints(length(lights.data))
prob.quant <- qweibull(prob.grid , 1.5,4)
#Draw QQ plot
qqplot(prob.quant,lights.data)
#add red reference line
qqline(lights.data,col = 2)
2011 Jul 25
1
scripting qqplot and qqnorm
Hi all,
I am an R newbie, and I have a question about scripting. I have the
following lines which I want to put int\
o a script which I can call from the shell of a Mac/Linux machine :
myrns <- read.csv(file="/Users/vihan/test.csv",sep="",header=FALSE)
qqnorm(myrns)
qqline(myrns)
This works fine on an interactive R session.
However, as I understand the basic framework of
2003 Apr 29
4
thick plot lines
Dear People,
In a qqplot I am doing, I get lines/points that are very thick. I've tried
setting the lwd variable to 0.1, but it doesn't seem to have any effect.
Also, I have set the value of lty to dashed, but I still get dots. The
command looks like
qqplot(cdf.inv(seq(0,1,length=size),theta,pos,len),empmargdistvec(len,theta,pos,size),
       xlim=c(-theta,theta), ylim=c(-theta,theta),
2012 Feb 10
1
making multiple lines using qqplot
Hi Everyone,
I want to make 3 lines on the same graph (not as subplots, all in the same
window, one on top of each other) and I want them to be quantile-quantile
plots (qqplot).  Essentially, I am looking for the equivalent of Matlab's
"hold on" command to use with qqplot.  I know I can use 'points' or 'lines',
but these do not give me a qqplot (only appear to work
2006 Feb 06
2
qqplot
Hello,
I would like to use qqplot() to compare two
experimental distributions. But I do not understand
how qqplot() compute quantiles. In fact, quantile() do
not return the same results.
Thank you for your help.
Vincent.
2011 Mar 25
1
multiple plots with QQplot of PerformanceAnalytics
Hi All,
I am trying to plot 4 graphs on to 1 page using layout(...), or par(mfcol = 
c(...)); with the function QQplot from the package PerformanceAnalytics.
The problem is that, no matter what order I use, it only plots 3 graphs on to 1 
page and the last QQplot is shunted to the next page.
Also, this only happens to the QQplot, i.e. there is no problem with 4 
Histograms. 
set.seed(1033)
data
2001 Jan 05
1
pairs(NxK_Matrix,panel=qqplot) (PR#803)
Full_Name: Matthias von Davier
Version: 1.2.0
OS: linux
Submission from: (NULL) (144.81.31.148)
pairs(NxK_Matrix,panel=qqplot)
produces a message
Error in pairs.default(NxK_Matrix,panel=qqplot) :
   The panel function made a new plot
best regards and a happy new year
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1999 Aug 31
1
Suggestion for qqplot() improvement
>>>>> On Tue, 31 Aug 1999 14:57, Werner Stahel <stahel@stat.math.ethz.ch> said:
    WSt> Here is a suggestion.  It seems that qqplots, comparing a sample
    WSt> to a distribution other than the normal, are not explicitly
    WSt> available in S or R. I found
(in S-plus / Trellis it is, see below)
    WSt>	   qqplot(y, rt(300, df = 5))
    WSt> as an
2011 Nov 16
2
outlier identify in qqplot
Dear Community, 
I want to identify outliers in my data. I don't know how to use identify
command in the plots obtained. 
I've gone through help files and use mahalanobis example for my purpose: 
NormalMultivarianteComparefunc <- function(x) { 
  
	Sx <- cov(x)
	D2 <- mahalanobis(x, colMeans(x), Sx)
	plot(density(D2, bw=.5), main="Squared Mahalanobis distances, n=nrow(x),
2012 Nov 29
1
QQplot
Hi! 
<http://r.789695.n4.nabble.com/file/n4651293/qq.png> 
We are stuck with a problem considering the qqplot of a dataset. 
We are trying to discover what kind of distribution this is. We already
tried to normal, exponential or the logaritmical distribution but none of
those are able to solve our problem. Is there someone able to tell us what
kind deformation we should try? 
(I'm
2006 Mar 15
1
(newbie) Weighted qqplot?
Folks,
Normally, in a data frame, one observation counts as one observation
of the distribution. Thus one can easily produce a CDF and (in Splus
atleast) use cdf.compare to compare the CDF (BTW: what is the R
equivalent of the SPlus cdf.compare() function, if any?)
However, if each point should not count equally, how can I weight the
points before comparing the distributions? I was thinking of
2008 Mar 04
2
paired or one-sample t-Test
Hi Guys,
I am having a real hard time trying to figure out for microarry.
Here is my code
One-Sample t-Test
dim(data.sub)
[1] 10000   140 ##there are 10000 probesets and 140 columns 
hist(data.sub) ## Histogram. Identify if the probesets are normal
distributed
q<-rnorm(10000) ##generate 10000 random, normal distributed values
qqplot(data.sub,q)) ##Show the plot of the probeset
2001 Oct 16
5
help me
Hy,
I have dowloaded the R-version for Windows.
I would want to plot different pictures on the same device, but I am not
able to do it (i.e I would like make 2 qqplot on the same graphic).
Can you help me?
Thanks in advance
Davide 
reply to: d.tarfanelli at libero.it
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2008 Aug 05
2
qqline function doesn't plot
I have a data vector x.  When I try 
qqline(x)
I get the following error:
Error in int_abline(a = a, b = b, h = h, v = v, untf = untf, ...) : 
  plot.new has not been called yet
And a blank plot appears.
Can anybody help?  What am I doing wrong?
Thanks,
Scotty
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2010 May 29
3
adding statistical output to a plot
I have written a function to emulate minitab's QQ plotting output (with SW
test and AD test results on the graph):
mtab.norm<-function(x)
{ library(nortest)
library(lattice)
x<-as.numeric(x)
x<-as.vector(x)
plot.ht<-4.6
plot.wd<-4.6
pt.ht=plot.ht/5
txt.sz<-(plot.ht/7.5)
X11(width=plot.wd, height=plot.ht, bg='gray96')
qqplot(x, pch=16, cex=pt.ht,
2006 Feb 01
1
Difficulty with qqline in logarithmic context
Hi, R friends.  I had some difficulty with the following code:
   qqnorm(freq, log='y')
   qqline(freq)
as the line drawn was seemingly random.  The exact data I used appears 
below.  After wandering a bit within the source code for "abline", 
I figured out I should rather write:
   qqnorm(freq, log='y')
   par(ylog=FALSE)
   qqline(log10(freq))
   par(ylog=TRUE)
2011 Apr 30
4
QQ plot for normality testing
Hi all, 
 
I am trying to test wheater the distribution of my samples is normal with QQ plot. 
 
I have a values of water content in clays in around few hundred samples. Is the code :
 
qqnorm(w)      #w being water content
qqline(w)
 
 
sufficient? 
 
How do I know when I get the plots which distribution is normal and which is not? 
 
Thanks, m
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2007 Nov 30
6
Generating a value
How do I generate a value in R from a poisson distribution with mean 20?
Thanks!
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