Displaying 20 results from an estimated 2000 matches similar to: "Confidence Interval"
2007 Sep 26
3
Scientific Notation
Dear List:
Below is how I specify an axis:
axis(2, at=c(0.00005, 0.0005))
R displays the numbers in scientific notation. What
argument/parameter should I use to tell R to display the numbers as
specified rather than in scientific notation?
> version
_
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major
2008 Nov 25
2
Heat Maps
Dear List,
Does there exist a function that produces a heat map like this one
(image 3 of 4):
http://www.tdameritrade.com/tradingtools/options360.html?a=HDY&referrer=http%3A%2F%2Fquery.nytimes.com%2Fsearch%2Fsitesearch%3Fquery%3Dheatmaptype%3Dnyt
In addition to colors, two other main features I am intersted in are:
1. Proportionality in the size of the grid.
2. Mose-over capability.
I may
2007 Sep 07
1
How to obtain parameters of a mixture model of two lognormal distributions
Dear List,
I have read that a lognormal mixture model having a pdf of the form
f(x)=w1*f1(x)+(1-w1)*f2(x) fits most data sets quite well, where f1
and f2 are lognormal distributions.
Any pointers on how to create a function that would produce the 5
parameters of f(x) would be greatly appreciated.
> version
_
platform i386-pc-mingw32
arch i386
os
2009 May 09
2
Histogram frequencies with a normal pdf curve overlay
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,
2007 Jul 23
3
Aggregate daily data into weekly sums
Dear Lest,
I have a two-variable data frame as follows (the time peirod of the
actual data set is 10 years):
Date Amount
1 6/1/2007 1
2 6/1/2007 1
3 6/4/2007 2
4 6/5/2007 2
5 6/11/2007 3
6 6/12/2007 3
7 6/12/2007 3
8 6/13/2007 3
9 6/13/2007 3
10 6/18/2007 4
11 6/18/2007 4
12 6/25/2007 5
13 6/28/2007 5
2007 Sep 26
2
Password-protect script files
Dear List,
Is there any way to password-protect script files (either within R or
otherwise)?
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor 5.1
year 2007
month 06
day 27
svn rev 42083
language R
version.string R version 2.5.1 (2007-06-27)
2007 May 04
2
Alternatives to unlist()
Given the following, one of the things I am trying to see is what % of
draws are below a certain number:
lambda <- 3
rate <- 5
n <- 5
set.seed(123)
v <- replicate(n, rexp(rpois(1,lambda), rate))
vv <- unlist(v)
cat("% of draws below 0.1:", round(length(subset(vv, vv <
0.1))/length(vv)*100,0), "%\n")
In actuality, my lambda, rate, and n are 26, 10, 1000000,
2007 May 31
1
R keeps crashing when executing 'rlogspline'
Dear List,
I have a simple model as follows:
x <- rnorm(500)
library(logspline)
fit <- logspline(x)
n <- 1000000
y <- replicate(n, sum(rlogspline(rpois(1,10), fit))) # last line
The problem I keep getting is R crashes when doing the last line. It
seems to be fine if n is small, but not if n is 1000000. The message
I keep getting is:
"R for Windows GUI front-end has
2002 Jun 12
1
confidence intervals
Hello,
I wonder if anyone has a function for calculating confidence intervals for
ratios. I have mortality rates calculated for several groups from sample
data -- but these can be treated as ratios?). I am entertaining the idea of
bootstrapping them.
Any help would be greatly appreciated.
TIA, Marwan
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2005 Jan 07
3
lognorm
Hi!
I 've a problem to have a lognorm distribution with
mean=1 and var (or sigma)=1.
rlnorm(1000,0,0)
rlnorm(1000,1,1)
rlnorm(1000,0,1)
.... ?
Can you help me?
2012 Sep 01
2
help on setting boundaries for generating random numbers
Dear All,
is there a way to set low and high limits to a simulation with rlnorm()?
as an example:
a <-rlnorm(500,0.7,1)
I get the summary of
Min. 1st Qu. Median Mean 3rd Qu. Max.
0.1175 1.0590 2.1270 3.4870 4.0260 45.3800
I would like to set limits so that the simulated values minimum would be greater then 0.5 and maximum of less than 30. If during simulation a
2004 May 01
2
Generating Lognormal Random variables (PR#6843)
Full_Name: Anthony Gichangi
Version: 1.90
OS: Windows XP Pro
Submission from: (NULL) (130.225.131.206)
The function rlnorm generates negative values for lognormal distribution.
x- rlnorm(1000, meanlog = 0.6931472, sdlog = 1)
Regards
Anthony
2008 May 04
1
Is my understanding of rlnorm correct?
rlnorm takes two 'shaping' parameters: meanlog and sdlog.
meanlog would appear from the documentation to be the log of the mean.
eg if the desired mean is 1 then meanlog=0.
So to generate random values that fit a lognormal distribution I would
do this:
rlnorm(N , meanlog = log(mean) , sdlog = log(sd))
But when I check the mean I don't get it when sdlog>0. Interestingly I
2013 May 10
1
rlnorm(n, meanlog = 0, sdlog = 1)
Hi list,
Does anyone know the code behind rlnorm(n, meanlog = 0, sdlog = 1)? I am
going to write it in c#.
thanks
Alireza
[[alternative HTML version deleted]]
2010 Jun 21
2
How to predict the mean and variance of the dependent variable after regression
Hi, folks,
As seen in the following codes:
x1=rlnorm(10)
x2=rlnorm(10,mean=2)
y=rlnorm(10,mean=10)### Fake dataset
linmod=lm(log(y)~log(x1)+log(x2))
After the regression, I would like to know the mean of y. Since log(y) is
normal and y is lognormal, I need to know the mean and variance of log(y)
first. I tried mean (y) and mean(linmod), but either one is what I want.
Any tips?
Thanks in
2009 Feb 11
3
Generating Numbers With Certain Distribution in R
Dear all,
Is there a way to generate K numbers of integer (K = 10^6).
The maximum value of the integer is 200,000 and minimum is 1.
And the occurrences of this integer follows
a lognormal distribution.
- Gundala Viswanath
Jakarta - Indonesia
2008 Feb 20
3
reshaping data frame
Dear all,
I'm having a few problems trying to reshape a data frame. I tried with
reshape{stats} and melt{reshape} but I was missing something. Any help is
very welcome. Please find details below:
#################################
# data in its original shape:
indiv <- rep(c("A","B"),c(10,10))
level.1 <- rpois(20, lambda=3)
covar.1 <- rlnorm(20, 3, 1)
level.2
2005 Jun 29
2
MLE with optim
Hello,
I tried to fit a lognormal distribution by using optim. But sadly the output
seems to be incorrect.
Who can tell me where the "bug" is?
test = rlnorm(100,5,3)
logL = function(parm, x,...) -sum(log(dlnorm(x,parm,...)))
start = list(meanlog=5, sdlog=3)
optim(start,logL,x=test)$par
Carsten.
[[alternative HTML version deleted]]
2009 Jul 20
3
Histograms on a log scale
Dear All,
I would like to be able to plot histograms/densities on a semi-log or
log-log scale.
I found several suggestions online
http://tolstoy.newcastle.edu.au/R/help/05/09/12044.html
https://stat.ethz.ch/pipermail/r-help/2002-June/022295.html
http://www.harding.edu/fmccown/R/#histograms
Now, consider the code snippet taken from
http://www.harding.edu/fmccown/R/#histograms
# Get a random
2012 May 16
3
finding mean and SD for a log-normal distribution
Dear R Expert
allow me to ask a quick qestion: I have a mean value of 6 and a SD of 3 describing my distribution. I would like to "convert" this distribution into a log normal distribution that would best describe it when resimulated using log normal distribution. Currently I am using another software to estimate the respective mean and SD on the log scale and the results are: 1.6667