Dear list, I have a dataset containing values obtained from two different instruments (x and y). I want to generate 5 samples from normal distribution for each instrument based on their means and standard deviations. The problem is values from both instruments are non-negative, so if using rnorm I would get some negative values. Is there any options to determine the lower bound of normal distribution to be 0 or can I simulate the samples in different ways to avoid the negative values? > dat id x y 75 101 0.134 0.1911315 79 102 0.170 0.1610306 76 103 0.134 0.1911315 84 104 0.170 0.1610306 74 105 0.134 0.1911315 80 106 0.170 0.1610306 77 107 0.134 0.1911315 81 108 0.170 0.1610306 82 109 0.170 0.1610306 78 111 0.170 0.1610306 83 112 0.170 0.1610306 85 113 0.097 0.2777778 2 201 1.032 1.5510434 1 202 0.803 1.0631001 5 203 1.032 1.5510434 mu<-apply(dat[,-1],2,mean) sigma<-apply(dat[,-1],2,sd) len<-5 n<-20 s1<-vector("list",len) set.seed(7) for(i in 1:len){ s1[[i]]<-cbind.data.frame(x=rnorm(n*i,mean=mu[1],sd=sigma[1]), y=rnorm(n*i,mean=mu[2],sd=sigma[2])) } Thanks for any help, Tom
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