rgr (version 1.1.7)

ad.plot2: Plot Results of Analytical Duplicate Analyses, Alternate Input

Description

Function to prepare data stored in alternate forms from that expected by function ad.plot1 for its use. For further details see x in Arguments below. The data will be plotted as the percent absolute difference between duplicates relative to their means.

Usage

ad.plot2(x, xname = deparse(substitute(x)), if.order = TRUE, 
	if.rsds = FALSE, ldl = NULL, ad.tol = NULL, log = FALSE,
	ifalt = FALSE, ...)

Arguments

x

a column vector from a matrix or data frame, x[1], ..., x[2*n]. The default is that the first n members of the vector are the first measurements and the second n members are the duplicate measurements. If the measurements alternate, i.e. dup

xname

a title can be displayed with the plot and results, e.g., xname = "Cu (mg/kg)". If this field is undefined the character string for x is used as a default.

if.order

by default the analytical duplicate results are plotted in the order in which they occur in the data file, this usually corresponds to date of analysis in a time-series. Alternately, setting if.order = FALSE results in the individual duplica

if.rsds

by default the absolute difference between the duplicates expressed as a percentage of their mean is plotted on the y-axis. If it is required to plot the relative standard deviations (RSDs), set if.rsds = TRUE.

ldl

by default the x-axis is defined by the measurement units. If it is desired to express the duplicate means as a ratio to the lower detection limit (ldl) of the analytical procedure, then set ldl = 'ldl' in measurement units.

ad.tol

optionally a tolerance level my be provided for the maximum acceptable percent absolute relative difference between duplicates, in which case a red dotted line is added to the plot.

log

optionally the x-axis of the plot employing duplicate means may be plotted with logarithmic scaling, if so, set log = TRUE.

ifalt

set ifalt = TRUE to accommodate alternating sets of paired observations.

...

any additional arguments to be passed to the plot function for titling, etc.

Details

For further details see ad.plot1. If the data are as n duplicate pairs, x1 and x2, use function ad.plot1.

See Also

ad.plot1, ltdl.fix.df

Examples

## Make test data available
data(ad.test)
attach(ad.test)

## Plot analytical duplicate analyses as a time-series
ad.plot2(Cu, ifalt = TRUE)

## Plot analytical duplicate analyses versus duplicate means,
## annotating more appropriately, with a 20% maximum tolerance
ad.plot2(Cu, "Cu (mg/kg)", if.order = FALSE, ad.tol = 20, ifalt = TRUE)

## Detach test data
detach(ad.test)