Displaying 20 results from an estimated 2000 matches similar to: "Simple qqplot question"
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
2011 Jan 17
1
Problem about for loop
Hi everyones, my function like;
e <- rnorm(n=50, mean=0, sd=sqrt(0.5625))
x0 <- c(rep(1,50))
x1 <- rnorm(n=50,mean=2,sd=1)
x2 <- rnorm(n=50,mean=2,sd=1)
x3 <- rnorm(n=50,mean=2,sd=1)
x4 <- rnorm(n=50,mean=2,sd=1)
y <- 1+ 2*x1+4*x2+3*x3+2*x4+e
x2[1] = 10 #influential observarion
y[1] = 10 #influential observarion
data.x <- matrix(c(x0,x1,x2,x3,x4),ncol=5)
data.y
2011 Mar 20
2
Why unique(sample) decreases the performance ?
Hi,
I' am interested in differences between sample's result when samples consist
of full elements and consist of only distinct elements. When sample consist
of full elements it take about 120 sec., but when consist of only distinct
elements it take about 4.5 or 5 times more sec. I expected that opposite of
this result, because unique(sample) has less elements than full sample. Code
as
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 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
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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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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2009 Dec 23
2
how to create normal qqplot with the 95% confidence interval
hi everyone!
season's greetings!
is there any way that i can create a normal qqplot showing, aside from the
qqline, the 95% confidence limits? thank you very much..
happy holidays!
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2007 Mar 20
1
Symbol and Ellipsis problems
Hi Everyone,
When I have a load of functions which have various arguments passed
via the ellipsis argument it keeps on assigning them as symbol making
them unusable to the function. My current work around involves using
do.call but this is rather cumbersome.
Does anyone know why it suddenly changes the types to symbol and if
there is a way to get the actual data pointed to by the symbol? (I
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),
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),
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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2006 Jul 31
4
question about dataframe ("sensory") in PLS package
Dear all,
I am trying to my dataframe for the PLS analysis using the PLS package.
However I have some trouble generating the correct dataframe. The main
problem is how to use one name to represent several columns in the
dataframe.
The example dataframe in PLS package is called "sensory". I cannot
directly read the data file since it's a binary file. If I use
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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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)
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,
2009 Apr 26
3
Flipping axes of qqnorm
Hi all,
I have just started using R to produce qqnorm plots. I am trying to
switch the x and y axes so that the theoretical values are plotted on the y
axis and my data on the x axis. Can anyone help me with this?
Thanks
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2003 Oct 15
0
qqnorm(*, datax=TRUE, xlab,ylab) -- S+ compatibility problem
Just found because an old (written for S+) function of mine did
label plots wrongly with R.
Example --- inspired from example(qqnorm) ---
data(precip)
qqnorm(precip, ylab = "Precipitation [in/yr] ...")
qqnorm(precip, ylab = "Precipitation [in/yr] ...", datax = TRUE)
this is all "fine" -- `datax' is a switch that just switches the
axes but keeps the
2000 Dec 11
1
qqline (PR#764)
I think qqline does not do exactly what it is advertised to do ("`qqline'
adds a line to a normal quantile-quantile plot which passes through the
first and third quartiles."). Consider the graph:
tmp <- qnorm(ppoints(10))
qqnorm(tmp)
qqline(tmp)
The line (which I expected go through all the points), has a slightly
shallower slope than does the points plotted by qqnorm. I think
2009 Nov 06
4
PRUEBAS DE NORMALIDAD
Estimados todos:
Me es grato escribir a esta lista de ayuda para R, ya que comparto 100% la filosofĂa de Software libre en especial software en EstadĂstica ya que es la carrera que estoy siguiendo.
El motivo de este mensaje es por un par de dudas que no pude resolver:
1. He utilizado las funciones para realizar pruebas de normalidad (kolmogorov-smirnov, cuando n>50) y (Shapiro, cuando