Displaying 20 results from an estimated 10000 matches similar to: "under sample problem"
2005 Dec 01
1
Simulate Correlated data from complex sample
Dear List:
I have created some code to simulate data from a complex sample where
5000 students are nested in 50 schools. My code returns a dataframe with
a variable representing student achievement at a single time point. My
actual code for creating this is below.
What I would like to do is generate a second column of data that is
correlated with the first at .8 and has the same means within
2005 Jul 15
4
Can't get sample function from "An Introduction to R" to work
I'm trying to figure out R, a piece at a time, hours at a time... I
was trying to copy the sample function in, "An Introduction to R" (for
version 2.1.0) by W. N. Venables, D. M. Smith, page 42. Section 10.1
"Simple examples" provides a sample function which I tried to duplicate
(I'm using Mac OS X 10.3.9, and "R for Mac OS X Aqua GUI v1.11). The
following
2003 Nov 18
2
sampling without repetition
Hi,
I'm trying to write a function that will divide a given range of
numbers into 3 sets using sample(), without repetition. Currently I'm
trying this approach:
r <- 1:10
s1 <- sample(r,size=3)
Next, I want to remove the selected elements from r and sample() from
the remainder.
r <- r[ -(r=s1) ]
s2 <- sample(r,size=3)
When I go to remove the elements contained in s2 from
2008 Oct 20
2
calculating mean for samples
Hi everyone,
> does any one knows how can I calculate mean for different samples
> i.e. I have a data like this:
>
> s1 s2 s3 s4
> 1 0 0 0 1
> 2 1 0 1 0
> 3 0 0 0 0
> 4 0 0 0 0
> 5 0 1 0 1
> 6 1 0 0 0
> 7 0 0 0 0
> 8 0 0 0 0
> 9 0 0 0 0
> 10 0 0 0 1
>
> I need to make 5 different sample with 5
2011 Mar 07
3
generate 3 distinct random samples without replacement
Hello:
I wonder if I could get a little help with random sampling in R.
I have a vector of length 7375. I would like to draw 3 distinct random samples, each of length 100 without replacement. I have tried the following:
d1 <- 1:7375
set.seed(7)
i <- sample(d1, 100, replace=F)
s1 <- sort(d1[i])
s1
d2 <- d1[-i]
set.seed(77)
j <- sample(d2, 100, replace=F)
s2 <- sort(d2[j])
2010 Feb 01
0
working with taxonomic trees: sampling
Dear all,
I am working with taxonomic data, represented as a list of classes,
orders, families, genera and finally species.
> class(mydata)
[1] "data.frame"
> mode(mydata)
[1] "list"
> names(mydata)
[1] "tclass" "torder" "tfamily" "tgenus" "tspecies"
> length(mydata$tclass)
[1] 161590
The first 10
2005 Oct 03
6
sampling vectors
Hello Listers,
I am trying to sample a vector to create a new one of sample length,
witha sum equal to the sum of the initial vector:
initial = 10, 30, 10 (sum=50)
sample example = 5, 35, 10 (sum=50) or 25, 15, 10 (sum=50), etc ...
My problem is to control the sum, so it stays constant.
Any suggestions would be very helpful !
Thank you in advance,
Eric
2002 Dec 04
1
Mixture of Multivariate Gaussian Sample Data
Hey, I am confused about how to generate the sample data from a mixture of
Multivariate Gaussian ditribution.
For example, there are 2 component Gaussian with prior
probability of 0.4 and 0.6,
the means and variances are
u1=[1 1]', Cov1=[1 0;0 1]
and
u2=[-1 -1]', Cov2=[1 0;0 1]
repectively.
So how can I generate a sample of 500 data from the above mixture
distribution?
Thanks.
Fred
2011 May 19
2
trouble with summary tables with several variables using aggregate function
Dear all,
I am having trouble creating summary tables using aggregate function.
given the following table:
Var1 Var2 Var3 dummy
S1 T1 I 1
S1 T1 I 1
S1 T1 D 1
S1 T1 D 1
S1 T2 I 1
S1 T2 I 1
S1 T2 D 1
S1 T2 D 1
S2
2005 Dec 01
2
Minimizing a Function with three Parameters
Hi,
I'm trying to get maximum likelihood estimates of \alpha, \beta_0 and
\beta_1, this can be achieved by solving the following three equations:
n / \alpha + \sum\limits_{i=1}^{n} ln(\psihat(i)) -
\sum\limits_{i=1}^{n} ( ln(x_i + \psihat(i)) ) = 0
\alpha \sum\limits_{i=1}^{n} 1/(psihat(i)) - (\alpha+1)
\sum\limits_{i=1}^{n} ( 1 / (x_i + \psihat(i)) ) = 0
\alpha \sum\limits_{i=1}^{n} (
2010 May 03
1
Comparing the correlations coefficient of two (very) dependent samples
Hello all,
I believe this can be done using bootstrap, but I am wondering if there is
some other way that might be used to tackle this.
#Let's say I have two pairs of samples:
set.seed(100)
s1 <- rnorm(100)
s2 <- s1 + rnorm(100)
x1 <- s1[1:99]
y1 <- s2[1:99]
x2 <- x1
y2 <- s2[2:100]
#And both yield the following two correlations:
cor(x1,y1) # 0.7568969 (cor1)
cor(x2,y2)
2004 Oct 12
5
[LLVMdev] set_intersect and Visual C compiler
On Tue, 12 Oct 2004 14:01:21 -0500 (CDT)
Chris Lattner <sabre at nondot.org> wrote:
> On Tue, 12 Oct 2004, Morten Ofstad wrote:
>
> > This is my first post on this mailing list, so bear with me... My name
> > is Morten Ofstad and I work for Hue AS (www.hue.no), a company that
> > makes 3D Visualization software. We are looking into using LLVM for JIT
> >
2012 Nov 01
2
[LLVMdev] llvm linking issue
I have three modules:
-----------------------------------------------------------------
s1.ll:
%0 = type <{ i32, i32 }>
define void @s1(%0* byval %myStruct) nounwind {
return:
ret void
}
-----------------------------------------------------------------
s2.ll:
%0 = type <{ i32, i32 }>
define void @s2(%0* byval %myStruct) nounwind {
return:
ret void
}
2009 Oct 11
1
Solving a nonlinear System of equations
Hello there,
I wish to solve the following nonlinear System of equations:
+ u1 - Vmax11*S1/(S1 + Km11 *(1 + S2/Km21)) - Vmax12*S1/( S1 + Km12 *(1+S2/Km22)) == 0
+ u2 - Vmax22*S2/(S2 + Km22 *(1 + S1/Km12)) - Vmax21*S2/( S2 + Km21 *(1+S1/Km11)) == 0
+ Vmax11*S1/(S1 + Km11 *(1 + S2/Km21)) + Vmax12*S1/( S1 + Km12 *(1+S2/Km22)) - d1*P1 == 0
+ Vmax22*S2/(S2 + Km22 *(1 + S1/Km12)) + Vmax21*S2/( S2 +
2007 Sep 28
2
Problem with hard links
Hello,
I have a problem with rsync and hard links :
I have 1 folder : P, with 2 subfolders : S1 and S2
S2 contains a lot of hard links to file stored in folder S1.
P : -S1
-S2 (S2 files hard links to S1 files)
I would like to rsync the folder P to another computer, but each sub folder
S1 (110 Go) and S2 (10 Go + hard link to 100 Go of S1) contains thousands of
thousands of
2008 Oct 15
2
Help Help with sampling
Hi everyone,
I have a dataset(named "Mydata") which includes 4 different variables named;
s1,s2,s3,s4 .Each variable(symptom) has 14 patients.
I need to use random sampling to make, 5 different samples from my data with
5 patients in each sample. i.e. using all 4 variables I need to make 5
different samples by changing patients(with 5 patients in each sample).
X8 X9 X10 X102 X110
2011 Feb 02
4
Testing whether a number belong to a set
Hello everyone,
I am stuck with an apparently simple issue :
i) I have two sets S1 and S2, each containing a large number of integers,
say zip codes.
ii) Now, I just want to test whether a particular zip code belong to S1 or
S2 or neither of them.
iii) If it belongs to S1, the area/region gets a particular label, say 1; if
it belongs to S2, it gets a label 2 and if it doesnot belong to either S1
2017 Feb 06
2
[PATCH] Optimize silk_warped_autocorrelation_FIX() for ARM NEON
Hi Jean-Marc,
Thanks a lot for reviewing this huge assembly function!
silk_warped_autocorrelation_FIX_c()'s kernel part is
for( n = 0; n < length; n++ ) {
tmp1_QS = silk_LSHIFT32( (opus_int32)input[ n ], QS );
/* Loop over allpass sections */
for( i = 0; i < order; i++ ) {
/* Output of allpass section */
tmp2_QS = silk_SMLAWB(
2004 Oct 12
3
[LLVMdev] set_intersect and Visual C compiler
Hello,
This is my first post on this mailing list, so bear with me... My name
is Morten Ofstad and I work for Hue AS (www.hue.no), a company that
makes 3D Visualization software. We are looking into using LLVM for JIT
compiling shader programs, to replace our own (slow) VM. A requirement
for this is that we can compile LLVM in VS7.1, so I contacted Paolo
Invernizzi to find the status of his
2009 Jul 08
2
Two-way ANOVA gives different results using anova(lm()) than doing it by hand
Hey!
Could you please take a quick look at what I have done? Somehow I get wrong results using the anova(lm()) combination compared to doing a two way ANOVA by hand.
Running:
Data<-read.table("Data.txt");
g<-lm(ExM~S1*S2,Data);
anova(g);
Gives:
Analysis of Variance Table
Response: ExM
Df Sum Sq Mean Sq F value Pr(>F)
S1 1 4.3679