# getPercentilePlottingPositions: Determination of percentile plotting positions for linear... In WeibullR: Weibull Analysis for Reliability Engineering

## Description

Determination of plotting positions to be used for linear regression of life data analysis is a highly debated topic. This function implements a wide assortment of options for the Weibull-R project.

## Usage

 ```1 2``` ```getPercentilePlottingPositions(x, s=NULL, interval=NULL, ppos="beta", aranks="Johnson", ties="none") ```

## Arguments

 `x` Either a dataframe containing at least `\$time` and `\$event` columns and optionally a `\$qty` column, or a vector of class `"numeric"` or `"integer"` with (life-)time observations. `s` An optional vector of suspension data. `interval` reserved argument for interval censored data - NOT YET IMPLEMENTED. `ppos` A string defining a plotting position method. Implemented options include "beta" the incomplete beta function (as default), "Benard", "mean" also known as Herd-Johnson, "Hazen" or modified Kaplan-Meier, "Kaplan-Meier" with modification for final complete failure, and "Blom. `aranks` A string defining the method for establishing adjusted ranks when suspension data (right censored) are present. Implemented options include "Johnson" (as default) and "KMestimator" `ties` A string defining a method of eliminating ties, or duplicate time valued data, from plotting. Implemented options include "highest" (used as 'Inspection Option #1' by Abernethy), "mean", "lowest", and "sequential".

## Value

Returns a dataframe with the failure data (as potentially reduced by ties argument), the probability plotting positions, and adjusted ranks.

## References

Robert B. Abernethy, (2008) "The New Weibull Handbook, Fifth Edition"

Leonard C. Johnson (1964) "The Statistical Treatment of Fatigue Experiments"

## Examples

 ```1 2 3``` ```failures<-c(90,96,30,49,82) suspensions<-c(100,45,10) median_percentile_ranks<-getPPP(failures,suspensions)[,2] ```

WeibullR documentation built on July 27, 2018, 3 p.m.