percentile.ple: Calculate Nonparametric Estimate of Xp and Confidence Limits

In STAND: Statistical Analysis of Non-Detects

Description

Find Xp, the 100pth percentile, and the 100γ% nonparametric confidence limits from PLE of F(x).

Usage

percentile.ple(dd, p = 0.95, gam = 0.95, interp = TRUE)

Arguments

dd	An n by 2 matrix or data frame with x (exposure) variable in column 1, and det= 0 for non-detect or 1 for detect in column 2
p	Find x such that the PLE of F(x) = p. Default 0.95
gam	one-sided confidence level γ. Default is 0.95
interp	if interp is TRUE use linear interpolation. Default TRUE

Details

Find Xp the 100pth percentile and confidence limits from the PLE of F(x) – see plekm for additional details. If interp is TRUE use linear interpolation; otherwise, the upper confidence limit (UCL) for Xp, UX(p,γ), is the smallest value of x such that the LCL for F(x) is ≥ p, the lower confidence limit (LCL), LX(p,γ), is the largest value of x such that the UCL for F(x) is ≤ p.

Value

A list with components:

Xp	PLE of the 100pth percentile
LXp	PLE of LX(p,γ) the 100*γ% LCL for Xp
UXp	PLE of UX(p,γ) the 100*γ% UCL for Xp
p	probability for Xp the 100pth percentile
gam	one-sided confidence level γ. Default is 0.95

Author(s)

E. L. Frome

References

Frome, E. L. and Wambach, P. F. (2005), "Statistical Methods and Software for the Analysis of Occupational Exposure Data with Non-Detectable Values," ORNL/TM-2005/52,Oak Ridge National Laboratory, Oak Ridge, TN 37830. Available at: http://www.csm.ornl.gov/esh/aoed/ORNLTM2005-52.pdf

See Also

See Also as plekm and SESdata

Examples

# use data from example 2 in ORNL/TM-2005/52 to calculate
# 95 percent UCL for 95th percentile
data(beTWA) 
unlist(percentile.ple(beTWA))
unlist(percentile.ml(beTWA)) # compare ML estimates

STAND documentation built on May 2, 2019, 3:39 p.m.