rgr (version 1.1.15)

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 accession order or 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. duplicate pair 1 measurement 1 followed by measurement 2, etc., set ifalt = TRUE.

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 duplicate results being plotted against their means.

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 may 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

Data may be as a single concatenated vector from a matrix or data frame as x1[1], ..., x1[n] followed by x[n+1], ..., x[2n], or alternated as x[1] and x[2] being a pair through to x[2*i+1] and x[2*i+2] for the i in 1:n duplicate pairs, see ifalt.

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

See Also

ad.plot1, ad.plot4, ltdl.fix.df

Examples

# NOT RUN {
## 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)
# }