From: D Cornacchia <cornaclia_at_rogers.com>

Date: Wed, 09 Jun 2010 19:11:53 -0400

CV <- function(x) sqrt(var(x))/mean(x)

CV(x)

CV(boot)

N <- boot

CV(x)

CV(sample(x,replace=T))

boot <-numeric(991)

for (i in 1:991) boot[i] <- CV(sample(x,replace=T)) CV(boot)

stderr(boot)

P <- boot

hist(N)

t.test (x, N)

ks.test(x, N)

R-help_at_r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Wed 09 Jun 2010 - 23:16:55 GMT

Date: Wed, 09 Jun 2010 19:11:53 -0400

Dear R-Helpers,

I am trying to bootstrap the coefficient of variation on a suite of vectors, here I provide an example using one of the vectors in my study. When I ran this script with the vector x <-c(0.625, 0.071428571, 0.133333333, 0.125, 0), it returned CV(boot) [the second one], and stderr(boot) [the second one] without problem. However, when I ran it with the vector in the following example, I received NA for the latter two statistics. I cannot figure out what is missing, why it won't work with this vector, and how I can rectify this situation. Your input would be greatly appreciated!

x <-c(1, 0, 0.153846154, 0, 0.142857143)
mean (x)

sample(x,replace=T)

mean(sample(x,replace=T))

boot <-numeric(991)

for (i in 1:991) boot[i] <- mean(sample(x,replace=T))
mean(boot)

var(boot)

sd(boot)

stderr <- function(boot) sqrt(var(boot)/length(boot))
stderr(boot)

median(boot)

min(boot)

max(boot)

range(boot)

IQR(boot)

quantile(boot,0.975)

quantile(boot,0.025)

bias <- mean(boot) - mean(x)

mean(x) - bias mean(x) - bias - 1.96*sqrt(var(boot)) mean(x) - bias + 1.96*sqrt(var(boot))

CV <- function(x) sqrt(var(x))/mean(x)

CV(x)

CV(boot)

N <- boot

CV(x)

CV(sample(x,replace=T))

boot <-numeric(991)

for (i in 1:991) boot[i] <- CV(sample(x,replace=T)) CV(boot)

stderr(boot)

P <- boot

hist(N)

t.test (x, N)

ks.test(x, N)

Many thanks,

D.

p.s. I am very new to R.

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Wed 09 Jun 2010 - 23:16:55 GMT

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