Displaying 20 results from an estimated 3000 matches similar to: "how to use apply with two variables"
2010 Jun 23
2
About normality tests...
Hi all,
I have two very large samples of data (10000+ data points) and would
like to perform normality tests on it. I know that p < .05 means that
a data set is considered as not normal with any of the two tests. I am
also aware that large samples tend to lead more likely to normal
results (Andy Field, 2005).
I have a few questions to ensure that I am using them right.
1) The Shapiro-Wilk
2010 Jun 29
1
Sweave, xtable plus/minus sign
Dear R-users,
please consider the following minimal example:
\documentclass[a4paper,titlepage,onecolumn,12pt]{article}
\usepackage[italian]{babel}
\usepackage{amssymb}
\usepackage[utf8x]{inputenc}
\usepackage[pdftex]{graphicx}
\begin{document}
<<label=test, echo=FALSE, results=tex>>=
df.data1 <-
cbind.data.frame(A = rnorm(18),
B =factor(rep(LETTERS[1:6],
2007 Jul 07
1
calculating p-values of columns in a dataframe
I have a dataframe ("mydf") that contains "differences of means".
I wish to test whether these differences are significantly different from zero.
Below, I calculate the t-statistic for each column.
What is a "good" method to calculate/look-up the p-value for each column?
mydf=data.frame(a=c(1,-22,3,-4),b=c(5,-6,-7,9))
mymean=mean(mydf)
mysd=sd(mydf)
2007 Nov 28
4
Replacing values job
Hallo,
I have two vectors of different lengths which contain the same set of
values:
X < -c(2,6,1,7,4,3,5)
Y <- c(1,1,6,4,6,1,4,1,2,3,6,6,1,2,4,4,5,4,1,7,6,6,4,4,7,1,2)
How can I replace the values in Y with the index (!) of the corresponding
values in X. So 2 appears in X in the first coordinate, so all 2’s in Y
should be replaced by 1, etc.
Thank you for your help,
Serguei
2006 Dec 14
3
Delete all dimnames
Hello, how can I get rid of all dimnames so that:
$amat
Var3 Var2 Var1
8 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0
7 1 1 1 0 1 0 0 0 1 0 0 0 0 0 0
6 1 1 0 1 0 1 0 0 0 1 0 0 0 0 0
5 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0
4 1 0 1 1 0 0 1 0 0 0 0 1 0 0 0
3 1 0 1 0 0 0 0 0 0 0 0 0 1 0 0
2 1 0 0 1 0 0 0 0 0 0 0 0 0 1 0
1 1 0 0 0 0 0 0 0 0 0 0 0 0
2005 Nov 23
2
vector of permutated products
Given an x-vector with, say, 3 elements, I would like to compute the
following vector of permutated products
(1-x1)*(1-x2)*(1-x3)
(1-x1)*(1-x2)*x3
(1-x1)*x2*(1-x3)
x1*(1-x2)*(1-x3)
(1-x1)*x2*x3
x1*(1-x2)*x3
x1*x2*(1-x3)
x1*x2*x3
Now, I already have the correctly sorted matrix of permutations! So, the
input looks something like:
#input
x<-c(0.3,0.1,0.2)
Nx<-length(x)
Ncomb<-2^Nx
2007 Nov 28
1
Order observations in a dataframe
Dear All,
Suppose I have the following dataframe:
country;weight;group
bul;10;1
cze;12;1
grc;12;1
hun;12;1
prt;12;1
rom14;1
fra;29;2
ita;29;2
gbr;29;2
aut;10;3
bel;12;3
The "group" variable denotes the id-number of a group of countries. How can
I re-label the groups in the descending order of their cumulative "weight",
which wound be:
country;weight;group
fra;29;1
ita;29;1
2005 Dec 04
4
Construct a data.frame in a FOR-loop
Say I have a FOR-loop for computing powers (just a trivial example)
for(i in 1:5)
{
x<-i^2
y<-i^3
}
How can I create a data.frame and a 3D plot of (i,x(i),y(i)), i.e. for
each iteration
Thanks,
Serguei Kaniovski
--
___________________________________________________________________
??sterreichisches Institut f??r Wirtschaftsforschung (WIFO)
Name: Serguei Kaniovski
2007 Feb 06
1
Questions on counts by case
Hi all,
for the data below I would like to
1. generate a dummy variable for each group "gr" of the same composition by
people, then save each portion in a separate file,
2. compute the frequency of "1"'s in "x" for each person by group
"gr". So, "mike" will have freq=2/3, as he has two "1" and one "0" in 3
groups.
2006 Sep 22
3
Compiling a contingency table of counts by case
I have asked a similar question before but this time
the problem is somewhat more involved. I have the
following data:
case;name;x
1;Joe;1
1;Mike;1
1;Zoe;1
2;Joe;1
2;Mike;0
2;Zoe;1
2;John;1
3;Mike;1
3;Zoe;0
3;Karl;0
I would like to count the number of "case"
in which any two "name"
a. both have "x=1",
b. the first has "x=0" - the second has
2007 Feb 26
1
Adding duplicates by rows
Hi,
I am trying to add duplicates of matrix "mat" by row. Commands
subset(mat,duplicated(rownames(mat)))
or
mat[which(duplicated(rownames(mat))),]
return only half of the required indices. How can I find the remaining
ones, ie the matches, so that I can add them up?
Thanks,
Serguei
___________________________________________________________________
Austrian Institute of Economic
2008 Dec 24
1
Implementing a linear restriction in lm()
Dear All!
I want to test a coeffcient restriction beta=1 in a univariate model lm
(y~x). Entering
lm((y-x)~1) does not help since anova test requires the same dependent
variable. What is the right way to proceed?
Thank you for your help and marry xmas,
Serguei Kaniovski
________________________________________
Austrian Institute of Economic Research (WIFO)
2006 Oct 03
1
Reshape into a contingency table/Fisher's test
Dear all,
how can I "reshape"/"cast" the following matrix
00;01;10;11
John.Mike;123;313;12;31
John.Jim;54;57;39;36
John.Steve;135;47;47;74
Mike.Jim;63;37;27;16
Mike.Steve;15;15;5;61
Jim.Steve;6;10;34;35
into a set of stacked 2x2 contingency tables
0;1
John;123;12
Mike;313;31
John;54;39
Jim;57;36
John;135;47
Steve;47;16
...
so that the "fisher.test" and
2006 Dec 04
1
Count cases by indicator
Hi,
In the data below, "case" represents cases, "x" binary states. Each
"case" has exactly 9 "x", ie is a binary vector of length 9.
There are 2^9=512 possible combinations of binary states in a given
"case", ie 512 possible vectors. I generate these in the order of the
decimals the vectors represent, as:
2007 Dec 05
1
Information criteria for kmeans
Hello,
how is, for example, the Schwarz criterion is defined for kmeans? It should
be something like:
k <- 2
vars <- 4
nobs <- 100
dat <- rbind(matrix(rnorm(nobs, sd = 0.3), ncol = vars),
matrix(rnorm(nobs, mean = 1, sd = 0.3), ncol = vars))
colnames(dat) <- paste("var",1:4)
(cl <- kmeans(dat, k))
schwarz <- sum(cl$withinss)+ vars*k*log(nobs)
Thanks
2006 Jul 18
2
A contingency table of counts by case
Here is an example of the data.frame that I have,
df<-data.frame("case"=rep(1:5,each=9),"id"=rep(1:9,times=5),"x"=round(runif(length(rep(1:5,each=9)))))
"case" represents the cases,
"id" the persons, and
"x" is the binary state.
I would like to know in how many cases any two persons
a. both have "1",
b. the first has
2009 Jun 26
3
Compute correlation matrix for panel data with specific ordering
Hello All,
I have a panel date - here a small-scale example:
df <-
data.frame(cbind(rep(c("AUT","BEL","DEN","GER"),4),cbind(rep(c(1999,2000,2001,2002),4)),sample(10,16,replace=T)))
names(df) <- c("country","year","x")
SORT <- c("GER","BEL","DEN","AUT")
I need to compute the
2008 Jan 14
2
Permutations of variables in a dataframe
Hallo All,
I would like to apply a function to all permutations of variables in a
dataframe (except the first). What is the best way to achieve this?
I produce the permutations using:
nvar <- ncol(dat) - 1
perms <- as.matrix( expand.grid(rep( list(1:0) , nvar ))[ , nvar:1] )
Thanks in advance
Serguei
Test-dataframe, comma-delimited:
code,wav,w,area,gdp,def,pop,coast,milspend,agr
2009 Apr 18
5
Dummy (factor) based on a pair of variables
Dear All!
my data is on pairs of countries, i and j, e.g.:
y,i,j
1,AUT,BEL
2,AUT,GER
3,BEL,GER
I would like to create a dummy (indicator) variable for use in regression
(using factor?), such that it takes the value of 1 if the country is in the
pair (i.e. EITHER an i-country OR an j-country).
Thank you for your help,
Serguei
________________________________________
Austrian Institute of
2002 Apr 30
1
MemoryProblem in R-1.4.1
Hi all,
In a simulation context, I'm applying some my function, "myfun" say, to a
list of glm obj, "list.glm":
>length(list.glm) #number of samples simulated
[1] 1000
>class(list.glm[[324]]) #any component of the list
[1] "glm" "lm"
>length(list.glm[[290]]$y) #sample size
[1] 1000
Because length(list.glm) and the sample size are rather large,