# barplot.mandel.kh: Barplot of Mandel's h or k statistics In metRology: Support for Metrological Applications

## Description

`barplot.mandel.kh` produces a bar plot of Mandel's statistics, suitably grouped and with appropriate indicator lines for unusual values.

## Usage

 ```1 2 3 4 5 6 7 8 9``` ``` ## S3 method for class 'mandel.kh' barplot(height, probs = c(0.95, 0.99), main, xlab = attr(height, "grouped.by"), ylab = attr(height, "mandel.type"), separators = TRUE, zero.line = TRUE, ylim, p.adjust = "none", frame.plot = TRUE, ..., col.ind = 1, lty.ind = c(2, 1), lwd.ind = 1, col.sep = "lightgrey", lwd.sep = 1, lty.sep = 1, lwd.zero = 1, col.zero = 1, lty.zero = 1) ```

## Arguments

 `height` An object of class `'mandel.kh'` (the name is for consistency with `barplot`). `probs` Indicator lines are drawn for these probabilities. Note that `probs` is interpreted as specifying two-tailed probabilities for Mandel's h and one-sided (upper tail) probabilities for Mandel's k. `main` a main title for the plot. If missing, the default is ``` paste(deparse(substitute(x)), " - Mandel's", attr(x, "mandel.type"), if(attr(x, "mandel.method") == "robust") "(Robust variant)")``` `xlab` a label for the x axis; defaults to the `grouped.by` attribute for `x`. `ylab` a label for the x axis; defaults to the `mandel.type` attribute for `x`. `separators` Logical; if `TRUE`, separator lines are drawn between groups of values. `zero.line` logical; if `TRUE` a horizontal line is drawn at zero. `ylim` the y limits of the plot. For Mandel's k, the default lower limit is zero. `p.adjust` Correction method for probabilities. If not `"none"`, passed to `p.adjust` prior to calculating indicator lines. Usually, indicator lines are drawn without correction (that is, with `p.adjust="none"`); specifying a p-value correction effectively turns the Mandel's statistics into single outlier tests. `frame.plot` Logical; If `TRUE` a box is drawn around the plot. `...` Other (usually graphical) parameters passed to `barplot`. Note that some parameters appear after ... to prevent spurious argument matching inside `barplot.default`. `col.ind, lty.ind, lwd.ind` Graphical parameters used for the indicator lines, recyckled to `length(probs)`. For `attr(x, "mandel.type")=="h"` the graphical parameters are applied to negative as well as positive indicator lines, applied outwards from zero. `col.sep, lwd.sep, lty.sep` Graphical parameters used for the separator lines. `lwd.zero, col.zero, lty.zero` Graphical parameters used for the zero line.

## Details

Mandel's statistics are traditionally plotted for inter-laboratory study data, grouped by laboratory, to give a rapid graphical view of laboratory bias and relative precision. This plot produces a grouped, side-by-side bar plot.

For classical Mandel statistics, indicator lines are drawn based on `qmandelh` or `qmandelk` as appropriate. For robust variants, indicator lines use `qnorm` for the h statistic and `qf(probs, n, Inf)` for the k statistic. Note that this corresponds to taking the robust estimates of location and scale as true values, so will be somewhat anticonservative.

## Value

barplot.mandel.kh returns a numeric vector of mid-points of the groups along the x-axis.

## Author(s)

S Ellison s.ellison@lgc.co.uk

## References

Accuracy (trueness and precision) of measurement methods and results – Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method. ISO, Geneva (1994).

`mandel.h`, `mandel.k`, `mandel.kh`, `pmandelh`, `pmandelk` for probabilities, quantiles etc.

See `plot.mandel.kh` for the 'classic' Mandel plot.

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14``` ``` data(RMstudy) h <- with(RMstudy, mandel.h(RMstudy[2:9], g=Lab)) barplot(h, las=2) # Lab 4 shows consistent low bias; # Lab 23 several extreme values. #Use colours to identify particular measurands: barplot(h, las=2, col=1:8) legend("bottomleft", legend=names(h), fill=1:8, cex=0.7, bg="white") #Example of Mandel's k: k <- with(RMstudy, mandel.k(RMstudy[2:9], g=Lab)) barplot(k, las=2) # Lab 8 looks unusually variable; # Lab 14 unusually precise ```

### Example output   ```Attaching package: 'metRology'

The following objects are masked from 'package:base':

cbind, rbind
```

metRology documentation built on May 2, 2019, 12:20 p.m.