s.u {MBESS} | R Documentation |
Unbiased estimate of the population standard deviation
Description
Transforms the usual (and biased) estimate of the standard deviation into an unbiased estimator.
Usage
s.u(s=NULL, N=NULL, X=NULL)
Arguments
s |
the usual estimate of the standard deviation (i.e., the square root of the unibased estimate of the variance) |
N |
sample size |
X |
vector of scores in which the unbiased estimate of the standard deviation should be calculated |
Details
Returns the unbiased estimate for the standard deviation.
Value
The unbiased estimate for the standard deviation.
Author(s)
Ken Kelley (University of Notre Dame; KKelley@ND.Edu)
References
Holtzman, W. H. (1950). The unbiased estimate of the population variance and standard deviation. American Journal of Psychology, 63, 615–617.
Examples
set.seed(113)
X <- rnorm(10, 100, 15)
# Square root of the unbiased estimate of the variance (not unbiased)
var(X)^.5
# One way to implement the function.
s.u(s=var(X)^.5, N=length(X))
# Another way to implement the function.
s.u(X=X)
[Package MBESS version 4.9.3 Index]