similar to: sample() question

Hi all, I have some rough code to sample consecutive integers with length according to a vector of lengths #sample space (representing positions) pos<-c(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20) #sample lengths lengths<-c(2,3,2) From these two vectors I need a vector of sampled positions. the sampling is without replacement, making things tough as the sampled integers need

Hi all! I was wondering if you can help me with a little sampling issue I'm having in R. I have a database with 100 observations. I need to sample n=9 sample size, 200 times (i.e. get 200 samples of size 9). N (pop. size) =100 Each sample can't contain the same observation more than one time (i.e. the program needs to check if the obs. has already been sampled into the sample -

Dear friends, suppose my dataset is the following data: id<-1:9 x<-c(1,2,3,1,2,3,1,2,3) y<-c(1,1,1,2,2,2,3,3,3) data<-data.frame(id,x,y) id x y 1 1 1 1 2 2 2 1 3 3 3 1 4 4 1 2 5 5 2 2 6 6 3 2 7 7 1 3 8 8 2 3 9 9 3 3 i want to do sampling like this:say the sample size is 3. First: random sampling from x; Next ,random sampling from

Hi, I looked up the help file on sample(), but didn't find the info I was looking for. When sample() is used to resample from a distribution, e.g., bootstrap, how does it do it? Does it use an uniform distribution, e.g., runif(), or something else? And, when the help file says:"sample(x) generates a random permutation of the elements of x (or 1:x)", would I be correct if I

Hi, I am having trouble understanding how to approach a simulation: I have a sample of n=250 from a population of N=2,000 individuals, and I would like to use either permutation test or bootstrap to test whether this particular sample is significantly different from the values of any other random samples of the same population. I thought I needed to take random samples (but I am not sure how

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

Hi This is OT, but I need it for my simulation in R. I have a special case for sampling with replacement: instead of sampling once and replacing it immediately, I sample n times, and then replace all n items. So: N entities x samples with replacement each sample consists of n sub-samples WITHOUT replacement, which are all replaced before the next sample is drawn My question is: which

Hi! Thanks for taking the time to read this. The code below creates a graph that takes 100 samples that are between 5% and 15% of the population (400). What I'd like to do, however, is add two other sections to the graph. It would look something like this: from 1-100 samples take 100 samples that are between 5% and 15% of the population (400). From 101-200 take 100 samples that are between

Hello All, sample() only sample on one variable x. But I'm interested in sampling more than one variable without replacement. Suppose I have 3 vectors x, y, z. I want to draw samples from all three vectors such that the combination of the three elements in each draw is not the same as any previous draws. I could use expand.grid to generate a vector out of the three vectors. But when the

Full_Name: Michael Chajewski Version: 2.9.0 OS: Windows XP Submission from: (NULL) (150.108.71.185) I was programming a routine which kept reducing the array from which a random sample was taken, resulting in a single number. I discovered that when R attempts to sample from an object with only one number it does not reproduce/report the number but instead chooses a random number between 1 and

Hi Kirsten, I can run your example code but I can't quite follow your division of sampling. Can you restate the the task? Below is what I think you are asking for, but I have the feeling I may be off the mark. Set A: 400 samples, draw 100 in range of 5 to 15 Set B: 800 samples, draw 100 in range of 5 to 15 Set C: 300 samples, draw 100 in range of 5 to 15 Ben > On Aug 5, 2017, at

Hi Ben, That's exactly right! Except for each set it's the sample population that is 400, 800 or 300. I want to take 3 samples, each of 100, where only the population differs. I can do this separately, but I'm having trouble putting them all on the same graph. I'd like to have sample on the x axis (1-300) and estimate on the y axis. I want to show how population affects the

>> Hi, I am trying to draw a random sample from an household survey with sample weight. Is there any function in R or Splus which allows this. Regards, ******************************************************* Mehtabul Azam Department of Economics Southern Methodist University Dallas TX 75275-0496 Tel: (214) 214 938 3906 Email: mazam at smu.edu <mailto:mazam at smu.edu>

Dear WizaRds, I am struggling to compute correctly a cluster sampling design. I want to do one stage clustering with different parametric changes: Let M be the total number of clusters in the population, and m the number sampled. Let N be the total of elements in the population and n the number sampled. y are the values sampled. This is my example data: clus1 <-

Hey, I am hoping someone can help me with a sampling question. I have a data frame of 8 variables (the first column is the subjects' id): SubID CSE1 CSE2 CSE3 CSE4 WSE1 WSE2 WSE3 WSE4 1 6 5 6 2 6 2 2 4 2 6 4 7 2 6 6 2 3 3 5 5 5 5 5 5

R users, I am trying to generate a randomized weekday survey schedule that ensures even coverage of weekdays in the sample, where the distribution of variable DOW is random with respect to WEEK. To accomplish this I need to randomly sample without replacement two weekdays per week for each of 27 weeks (only 5 are shown). However, I need to sample from a sequence (3:7) that needs to be

Dear All, I wonder if you could help me. I have a table with a series of sites that I would like to sample from. The table has 5 columns: ID X Coordinate Y Coordinate Value Factor The conditions are that each site can be selected more than once and the probability of it being selected (or sampled) is proportional to a factor located in column 'Factor' I am novice in terms of R, and

Dear all, here I need to draw all possible samples of size 2, from a population, which is characterized by c(1,4,56, 3). Sampling will be done with replacement. Is there any direct R function to faciliate this darwing? ? Thanks for your help

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])

Dan Nordlund wrote: "It would be necessary to see the code for your 'brief test' before anyone could meaningfully comment on your results. But your results for a single test could have been a valid "random" result." I've re-created what I did below. The problem appears to be with the weighting process: the unweighted sample came out much closer to the actual