similar to: How to generate fake population (ie. not sample) data?

Hi all, I am meetting one problem.I am estimating the variability of a population using one sample.I must do two-side and one-side hypothesis test,and estimate the confidence interval,But I don't know which function I can use ! Thank you !

Basically, we have a population of 4,392 documents and we want to find out the number of patents per document. We don?t want to go through all 4,392 documents, but want a reliable sample size from which to draw inferences. I feel like this count data will not follow a normal distribution, but more like a Poisson (skewed right.) The problem is we don?t have much similar data to this data set, so

Hello everybody, I am sure this is a beginners' problem which is being asked recurrently every few months, but nevertheless I wasn't able to find the answer searching through the r-help list. So here is my problem: I would like to plot a set of points (y vs. x), a (linear) regression line through them, and on the second graph underneath the first one I would want to plot residuals vs. x.

Hi all, I'm usually comfortable using the *apply functions for vectorizing loops in R. However, my particular problem now is using it in a sequential operation, which uses values evaluated in an offset of the loop vector. Here is my example using a for loop approach: dat <- data.frame(year=rep(1970:1980,each=365),yday=1:365) dat$value <-

I am trying to confirm that the sample is not different from the population with respect to geographical respresentation for the following data: region population sample n_total s_total 1 north 1244 232 9077 1032 2 south 4333 100 9077 1032 3 east 1500 200 9077 1032 4

Hi, In Splus7 this statement xlrmN1 <- sample(c(0,1,2),400 ,prob=c(0.02 ,0.93 ,0.05 )) worked fine, but in R the interpreter reports that the length of the vector to chose c(0,1,2) is shorter than the size of many times I want to be selected from the vector c(0,1,2). Any good reason? See below the error. > xlrmN1 <- sample(c(0,1,2),400 ,prob=c(0.02 ,0.93 ,0.05 )) Error in

Hi, Does anyone know an instruction to perform a test (or to construct a confidence interval) for the variance of a normal population (distribution). The test statistic is (n-1)*S´^2/sigma^2 and has chi square (n-1) distribution. Thank you, Alexandra [[alternative HTML version deleted]]

Hi all, I've been struggling with some code and was wondering if you all could help. I am trying to generate a theoretical population of P people who are housed within X different units. Each unit follows the same structure- 10 people per unit, 8 of whom are junior and two of whom are senior. I'd like to create a unit ID and a unique identifier for each person (person ID, PID) in the

I am a physician examining an NHANES dataset available at the NCHS website: http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/demo_d.xpt http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/hdl_d.xpt http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/tchol_d.xpt Thank you to the R authors and the foreign package authors in particular. Importing from the SAS export

Hi ALL: Suppose you have a population of N <- 5 observations, x <- c(43, 28, 7, 61, 39). From that you can draw a maximum of 10 samples without replacement of size n <- 3. (Command choose(N,n) yields 10). For instance the samples I seek are 43, 61, 7 39, 7, 28 ...etc How can I get R to do that for me, to get an exhaustive list of samples of size n drawn without replacement

Hi, I'm doing a function that describe two populations in competition. that's the function that i wrote: exclusao<-function(n10, n20, k1, k2, alfa, beta, t){ n1<-k1-(alfa*n20) n2<-k2-(beta*n10) if(t==0){plot(t, n10, type='b', xlim=range(c(1:t),c (1:t)), ylim=range(n10, n20), xlab='tempo', ylab='tamanho populacional') points(t, n20, type='b',

Hello all, First I have done extensive searches on this forum and others and nothing seems to work. So I decided to post thinking someone could point me to the write post or give me some help. I have drawn a 100 samples from a fictitious population (N=1000), and then randomly selected 25% of the 100 samples. I would like to now merge the data.frame from the 100 samples with the data.frame for

Hi, I am new to R. I am trying to plot the decay of a population over time (0-50yrs). I have the initial population value (5000) and the mortality rate (0.26/yr) and I can't figure out how to apply this so I get a remaining population value each year. In excel (ignoring headings) I would put 5000 in A1, in B2 I would enter the formula A1*0.26, and then in A2 (the next years population) I

> Dear R-users! > > I am using R 1.0.0 and Windows NT 4.0. > Suppose I have a population of N=100 subjects, a binomial variable and a random sample of n=20 subjects from my population, giving 15 "successes". I am interested in obtaining a confidence interval for the proportion of "successes" in my population. In R, I can use > library(ctest) >

yearly 8% drift, 25% sd why are x and y so different (x and z look ok)? Does this have something to do with biases due to the relationship between population and sample-estimates as a function of n samples and sd? Or am I doing something wrong? ----------------------------------------------------------------------- set.seed( 1 ); x <- mean( rnorm( 100000, mean=0.08, sd=0.25 )); set.seed( 1

Hi guys, I am a biologist and an R newbie, and I'm learning how to create a simple population model. So, I have a population matrix ("pop")of 30 age classes of female (1:4 are non-breeders, 5:30 are breeders) which will be modelled for 100 years. > pop <- matrix(0,30,100) I then populate this matrix with 3 young adult females. > pop[5, 1] <- 3 I then want to run this

Dear useRs! I would like to list all possible samples of size n form a population of size N. Obviously, N must be small (up to 20??) for this to be possible. For example, let say that N = 3 and n = 2. Therefore, we can say we have units 1, 2 and 3. I believe all possible samples are : {1,2},{2,3} and {1,3}. I would like to emphasize that I am not looking for the number of different

Hi, I have two data sets; one is a population and the other a sample of that population. I am trying to plot both on the same trellis display. # Example data set with two numerical attributes and two categorical pop <- data.frame(var1=rnorm(2000, 2000, 500), var2=rnorm(2000, 2000, 500)) cat<-(runif(2000)<=.5)+0 for(i in 1:length(cat)){ if(cat[i] == 0){ pop[i,"cat1"] =

Dear List, I'm struggling with the signature writing cbind/rbind functions for a S4 class. First of all, I'm very happy that it is now possible to dispatch on ... I follow the example for "paste" in ?dotMethods, which works as far as this: ### start example setClass ("cbtest", representation = representation (data = "data.frame"),

Dear useRs, I wrote a function that simulates a stochastic model in discrete time. The problem is that the stochastic parameters should not be negative and sometimes they happen to be. How can I conditionate it to when it draws a negative number, it transforms into zero in that time step? Here is the function: stochastic_prost <- function(Fmean, Fsd, Smean, Ssd, f, s, n, time, out=FALSE,