Displaying 20 results from an estimated 4000 matches similar to: "Power curves"
2007 Feb 09
2
plotting derived values not raw
I am trying to plot the mean and standard error of three separate
conditions. For various reasons, I do not have access to the raw data from
which the mean and error were derived and would like to make error bar plots
utilizing only the actual mean and standard error values. Is there a way to
do this in R? Thanks for any help in advance.
james
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2008 Apr 14
2
Power curve for a wilcoxon test
Hi,
I am trying to write R code to produce a power curve to show how the power of a
Wilcoxon-test varies depending on the mean, with data generated from a uniform distribution. Any ideas how I should go about this?Louisa
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2010 Dec 27
3
Gamma & Lognormal Model
Dear,
I'm very new to R Gui and I have to make an assignment on Gamma Regressions.
Surfing on the web doesn't help me very much so i hope this forum may be a
step forward.
The question sounds as follows:
The data set is in the library MASS
first install library(MASS)
then type data(mammals)
attach(mammals)
Assignment:
Fit the gamma model and lognormal model for the mammals data.
2011 Jan 03
3
Inverse Gaussian Distribution
Dear,
I want to fit an inverse gaussion distribution to a data set.
The predictor variables are gender, area and agecategory.
For each of these variables I've defined a baseline
e.g.
#agecat: baseline is 3
data<-transform(data, agecat=C(factor(agecat,ordered=TRUE),
contr.treatment(n=6,base=3)))
The variable 'area' goes from A to F (6 areas: A,B,C,D,E,F)
How can i
2010 May 13
3
How ls() only functions or anything else but functions?
Hello,
How ls() only functions or only data objects (basically anything other than
functions) such as data.frame, numeric ...?
John
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2007 Jan 27
3
how to handle a longitudinal data
i have a data set with repeated measures on same people, structure like
below:
id x1 x2 ...
001 10 20 ...
001 8 45 ...
001 4 2 ...
002 ....
002 ...
002 ....
002 ....
003 ....
.......
what is the easist way to show how many observations for each subject id?
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2009 Jun 12
3
Replacing 0s with NA
Hello
I have a dataset in which I would like to replace 0s with NAs. There is a
lot of information on how to replace NAs with 0, but I have struggled to
find anything with regards to doing the reverse. Any recommendations would
be great.
Cheers
Christine
2004 Jun 09
3
Dot chart question
Running R 1.8.1 on a Windows machine
In dotchart, I would like to shrink the labels on the tick marks (that
is, the numbers) without shrinking anything else. I could not find this
in either the Rhelp archives or in ?dotchart, which recmmends cex to
avoid 'label overlap', but cex shrinks all the characters in the plot.
Is there a way to do this?
Thanks
Peter
Peter L. Flom, PhD
2007 Dec 19
3
median of binned values
Dear list,
I have a vector (array, table row, whatever is best) of frequency values
for categories (or bins), and I need to find the median category.
Trivial to do by hand, but I was wondering if there is a means to do it
in R in an elegant way.
The obvious medioan(vector) returns the median frequency for the binns,
and that is not what I want. i.e,:
freq
cat1 1
cat2 10
2010 Mar 02
1
sem package and growth curves
I have been working through the book "Applied longitudinal data analysis: modeling change and event occurrence" by Judith D. Singer and John B. Willett. I have been working examples using SAS and also using it as an opportunity for learning to use R for statistical analysis.
I ran into some difficulties in chapter 8 which deals with using structural equation modeling. I have tried to
2006 Jan 11
3
SPSS and R ? do they like each other?
... and is there also such a nice tool (like spss.get) for exporting
data frames to SPSS? write.table does not keep the data frame labels -
neither did the other exporting tools that I found.
Thanks!
Michael
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2010 Mar 01
3
setting the steps for x axis labels on plot
Hello, I'm new to R, I've been working with it for the last 2 weeks. I
am plotting some data and not getting the labels on the x axis I am
expecting on my plot.
my code reads
#hours in the day
h <- c(0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23)
#hp is a data frame with a pivot table of 25 columns (label and data
for 24 hours)
plot(h, as.matrix(hp[1,2:25]),
2005 May 19
2
laten class analysis
Dear List,
just a little question,
I am interested in Latent Class Analysis and
I guess if there is a package for this pourpose
thank for you help,
Simone
2008 Jun 06
5
request: a class having max frequency
Dear R users
I have a very basic question. I tried but could not find the required result. using
dat <- pima
f <- table(dat[,9])
> f
0 1
500 268
i want to find that class say "0" having maximum frequency i.e 500. I used
>which.max(f)
which provide
0
1
How can i get only the "0". Thanks and
best regards
Muhammad Azam
Ph.D. Student
Department of
2005 Nov 10
2
polynomials transformation
Dear All,
Need some help in polynomials transformation to get the coefficients. I have tried "poly.transform" as applied in S-plus but it does not work.
Thanks in advanced for any helps.
Regards.
Abd. Rahman Kassim (PhD)
Head Forest Ecology Branch
Forest Management & Ecology Program
Forestry and Conservation Division
Forest Research Institute Malaysia
Kepong 52109
Selangor,
2007 Sep 19
2
By() with method = spearman
I have a data set where I want the correlations between 2 variables
conditional on a students grade level.
This code works just fine.
by(tmp[,c('mtsc07', 'DCBASmathscoreSPRING')], tmp$Grade, cor,
use='complete', method='pearson')
However, this generates an error
by(tmp[,c('mtsc07', 'DCBASmathscoreSPRING')], tmp$Grade, cor,
use='complete',
2009 Dec 02
4
Finding cases in one subset that are closet to another subset
Good afternoon
Running R2.10.0 on Windows
I have a data frame that includes (among much else) a factor (In_2006) and a continuous variable (math_3_4). I would like to find the 2 cases for In_2006 = 0 that are closest to each case where In_2006 = 1.
My data looks like
In_2006 math_3_4
0 55.1
1 51.6
1 18.1
1 26.6
1 14.1
2008 Jul 29
1
Problem reading a particular file with read.spss()
Hi All:
I have a seemingly typical SPSS data file with 219 rows and 486
variables. When I attempt to read this file into R with read.spss() in
the foreign package, I consistently get a "crash". This is the sequence
of events:
> library(foreign)
> sessionInfo()
R version 2.7.1 Patched (2008-07-24 r46120)
i386-pc-mingw32
locale:
LC_COLLATE=English_United
2008 Feb 24
3
Newbie: Where is lmFit function?
Hi Everyone,
I am trying to use lmFit function; however, i cannot find it function
anywhere.
I have been trying to find the function in Bioconductor and elsewhere. I
re-install bioconductor source, update package and update R as well. no luck
Is there a command in R where i can just type, and it will download it for
me?
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2006 Feb 28
2
vector math: calculating a rolling 12 row product?
I have a dataframe of numeric values with 30 ?rows?
and 7 ?columns?.
For each column, beginning at ?row? 12 and down to
?row? 30, I wish to calculate the ?rolling 12 row
product?. I.e., within each column, I wish to
multiply all the values in row 1:12, 2:13,
19:30.
I wish to save the results as a new dataframe, which
will have 19 rows and 7 columns.