similar to: Sampling problems

Displaying 20 results from an estimated 1000 matches similar to: "Sampling problems"

2011 Oct 11
2
matrix multiplication
Dear all, Sorry to bother you with such a stupid question, but I just cannot find the solution to my problem. I'd like to use matrix multiplication for meanA and factorial 3. I use the command meanA%*%factorial 3. But everything I get is: Error in factorial3 %*% A : non-conformable arguments I know that the number of the columns of the first vector has to be the same number of rows of the
2017 Jul 13
2
about plotting a special case
Thanks, Jim. The code works, but I don't understand why you use q1090 <- quantile(DF1$B, probs=c()), rather than DF1$A? Also, how to add a legend for both points DF1 and DF2? On Wed, Jul 12, 2017 at 8:25 PM, Jim Lemon <drjimlemon at gmail.com> wrote: > Hi lily, > Here is the first plot: > > plot(DF1$A,DF1$B,pch=19,col="red") > meanA<-mean(DF1$A) >
2012 Jun 14
1
Question about sampling
Dear list I wish to extract from a population genotypized for 10 SNP a subsample of the same population of size n with similar allele frequencies. Essentially i have a matrix of 200 rows (df) like this Name,Condition,rs1385699_X,rs6625163_X,rs962458_X,Rs4658627_1, sample01,Case,1,1,1,-1 sample02,Control,1,1,1,1 sample06,Control,1,-1,1,0 sample10,Case,1,1,1,0 sample11,Control,1,1,1,1
2017 Aug 19
4
My very first loop!! I failed. May I have some start-up aid?
Dear all, I have a data similar to this: myframe<- data.frame (ID=c("Ernie", "Ernie","Ernie","Ernie"), Timestamp=c("24.09.2012 08:00", "24.09.2012 09:00", "24.09.2012 10:00", "25.09.2012 10:00"), Longitude=c("8.481","8.482","8.483","8.481"),
2011 Apr 08
3
random sampling with levels and with replacement
Dear all, i have a dataset of about 400 records , with a variable that has  two levels 40 bad and 360 good among other variables,how do i come up  with10 random samples that have the composition of as the main sample  but maintaining the 40 bad 360 good with replacement, i recently discovered that my random samples generated dont maintain the ratio. My code is as  : mysample <-
2009 Dec 21
3
Question About Repeat Random Sampling from a Data Frame
Good Morning: I've read many, many posts on the r-help system and I feel compelled to quickly admit that I am relatively new to R, I do have several reference books around me, but I cannot count myself among the fortunate who seem to strong programming intuition. I have a data set consisting of 1637 observations of five variables: tensile strength, yield strength, elongation, hardness and a
2011 Aug 12
1
Which Durbin-Watson is correct? (weights involved) - using durbinWatsonTest and dwtest (packages car and lmtest)
Hello! I have a data frame mysample (sorry for a long way of creating it below - but I need it in this form, and it works). I regress Y onto X1 through X11 - first without weights, then with weights: regtest1<-lm(Y~., data=mysample[-13])) regtest2<-lm(Y~., data=mysample[-13]),weights=mysample$weight) summary(regtest1) summary(regtest2) Then I calculate Durbin-Watson for both regressions
2017 Jul 13
2
about plotting a special case
Hi R users, I have a question about plotting. There is the dataframe below, while each row represents a record. If I want to plot on a A-B plot, i.e., x-axis represents A, while y-axis represents B values. However, I want to plot the mean value from records 1-10 as one point, while the 10th and 90th percentiles represent the error bars, such as one point in the attached example. I don't know
2017 Aug 19
0
My very first loop!! I failed. May I have some start-up aid?
Thank you for providing the example code... for the request of running it multiple times it would have helped if you could have confirmed that the example ran through without errors... there were a lot of mistakes in it. Look into using the reprex package to check your example next time. I don't do this kind of analysis... I really don't know what to expect from the functions. The
2017 Aug 19
0
My very first loop!! I failed. May I have some start-up aid?
[answers inline] On 18 August 2017 at 20:08, Dagmar <Ramgad82 at gmx.net> wrote: > > myframe<- data.frame (ID=c("Ernie", "Ernie","Ernie","Ernie"), > Timestamp=c("24.09.2012 08:00", "24.09.2012 09:00", "24.09.2012 10:00", > "25.09.2012 10:00"),
2017 Jul 13
0
about plotting a special case
Hi lily, Here is the first plot: plot(DF1$A,DF1$B,pch=19,col="red") meanA<-mean(DF1$A) meanB<-mean(DF1$B) points(meanA,meanB,pch=18,col="red") q1090<-quantile(DF1$B,probs=c(0.1,0.9)) library(plotrix) dispersion(meanA,meanB,q1090[2],q1090[1], intervals=FALSE,col="red") The same code will work for a second data frame, except that you would use
2009 Aug 20
2
boxplot with log="y" and values starting at 0
Hi, I'm working with a data.frame containing values between 0 and 22000. Most of the values are actually between 0 and 50 and the high ones are outliers. I want to generate a boxplot and since the outliers are extremely high, I need to scale the y scale logarithmically. Otherwise one wouldn't really see the boxes of the boxplot. boxplot(dat, log="y", ylim=c(0,
2012 Feb 16
1
how to get r-squared for a predefined curve or function with "other" data points
hello mailing list! i still consider myself an R beginner, so please bear with me if my questions seems strange. i'm in the field of biology, and have done consecutive hydraulic conductivity measurements in three parallels ("Sample"), resulting in three sets of conductivity values ("PLC" for percent loss of conductivity, relative to 100%) at multiple pressures
2009 Nov 13
2
help sample from large dataset - misleading error?
Hi All, I want to take a simple random sample from a large dataset, gly, but I'm getting an error message. Any help? dim(gly) [1] 112371 37 > s1 <- sample(gly,100) Error in `[.data.frame`(x, .Internal(sample(length(x), size, replace, : cannot take a sample larger than the population when 'replace = FALSE' Thanks, Rachel [[alternative HTML version
2003 Jun 18
2
Private: Problem with tapply/lapply and sample (PR#3286)
Full_Name: Peter Gedeck Version: R1.6.2 and R1.7.0 OS: Windows XP Submission from: (NULL) (194.191.169.72) Hello, I marked the bug report Private, as I don't want my email address on the web server. The problem that I found is best explained using an example. index <- 1:6 cluster <- c(1,1,1,2,2,3) tapply(index,cluster,sample) gives $"1" [1] 2 1 3 $"2" [1] 4 5
2009 May 21
3
Problems with sample variance
Dear R users, I am a beginner to R. I generated 1000 samples with 15 data in each sample I tried finding the variance for each sample I used the code: m=1000;n=15 > r<-rnorm(15000) > for(i in 1:m){ x=data[,i] v=var(x)} what I got was just the variance for the last sample i.e. the 1000th sample but what I want is 1000 variance. Does anyone know what I did wrong? Thanks Chloe Smith
2012 Nov 22
1
Partial dependence plot in randomForest package (all flat responses)
Hi, I'm trying to make a partial plot with package randomForest in R. After I perform my random forest object I type partialPlot(data.rforest, pred.data=act2, x.var=centroid, "C") where data.rforest is my randomforest object, act2 is the original dataset, centroid is one of the predictor and C is one of the classes in my response variable. Whatever predictor or response class I
2010 Aug 17
1
using color palette in persp
Hello! I am using persp to get a plot of a 32x48 matrix. data <- as.matrix(read.table(file="mySample.dat")) persp(data) And I'm having trouble with trying to give a z-dependent palette to it like rainbow (or any built in one would do). How to combine that with the "col" argument? nice day Szilvi -- View this message in context:
2007 Feb 27
3
looping
Greetings: I am looking for some help (probably really basic) with looping. What I want to do is repeatedly sample observations (about 100 per sample) from a large dataset (100,000 observations). I would like the samples labelled sample.1, sample.2, and so on (or some other suitably simple naming scheme). To do this manually I would >smp.1 <- sample(100000, 100) >sample.1 <-
2010 Apr 05
3
bootstrap confidence intervals, non iid
hello, i need to calculate ci's for each of 4 groups within a dataset, to be able to infere about differences in the variable "similarity". the problem is that data within groups is dependent, as assigned by the blocking-factor "site". my guess was to use a block bootstrap but samples within in these blocks / sites are not of same length. i was not able to find a method to