hdquantile {Hmisc} | R Documentation |
Harrell-Davis Distribution-Free Quantile Estimator
Description
Computes the Harrell-Davis (1982) quantile estimator and jacknife standard errors of quantiles. The quantile estimator is a weighted linear combination or order statistics in which the order statistics used in traditional nonparametric quantile estimators are given the greatest weight. In small samples the H-D estimator is more efficient than traditional ones, and the two methods are asymptotically equivalent. The H-D estimator is the limit of a bootstrap average as the number of bootstrap resamples becomes infinitely large.
Usage
hdquantile(x, probs = seq(0, 1, 0.25),
se = FALSE, na.rm = FALSE, names = TRUE, weights=FALSE)
Arguments
x |
a numeric vector |
probs |
vector of quantiles to compute |
se |
set to |
na.rm |
set to |
names |
set to |
weights |
set to |
Details
A Fortran routine is used to compute the jackknife leave-out-one
quantile estimates. Standard errors are not computed for quantiles 0 or
1 (NA
s are returned).
Value
A vector of quantiles. If se=TRUE
this vector will have an
attribute se
added to it, containing the standard errors. If
weights=TRUE
, also has a "weights"
attribute which is a matrix.
Author(s)
Frank Harrell
References
Harrell FE, Davis CE (1982): A new distribution-free quantile estimator. Biometrika 69:635-640.
Hutson AD, Ernst MD (2000): The exact bootstrap mean and variance of an L-estimator. J Roy Statist Soc B 62:89-94.
See Also
Examples
set.seed(1)
x <- runif(100)
hdquantile(x, (1:3)/4, se=TRUE)
## Not run:
# Compare jackknife standard errors with those from the bootstrap
library(boot)
boot(x, function(x,i) hdquantile(x[i], probs=(1:3)/4), R=400)
## End(Not run)