vstat: Variability statistics of quantitative analysis results
In quantchem: Quantitative chemical analysis: calibration and evaluation of results

Description Usage Arguments Details Value Author(s) See Also Examples

Estimate error propagation of results (inter- and intra-day, inter- and intra-batch etc.)

1	vstat(x, ...)

`x`	a data frame of results. Each column contain one serie of results
`...`	optionally, more data frames, if additional factor is taking into account

This function performs one-way or two-way ANOVA on given results and prints summary in the usable way. If we are checking variability only between and within one kind of series (days, batches), we construct a data frame with a result sets in its columns and call this function on such data.frame. In this case, we get variability analysis of between-series and within-series. If we want to check variability additionally for example between weeks, we group results in data frames for each week and call the function on all data frames. This will summarize error propagation concerning series and groups.

The ANOVA object is returned, containing additional columns:

`Percent`	Percentage indication of error propagation (total sum of squares is 100 percent
`SD`	Standard deviation (square root of Mean Sq)
`RSD`	Relative standard deviation (coefficient of variation)

There are also additional rows - lowest row gives overall (total) error, and if function is called on multiple data-frames, a row containing variability between all series (sum of within-groups and between-groups) is given.

Lukasz Komsta

dstat

set.seed(1234)
week1 = data.frame(mon=rnorm(6),tue=rnorm(6),wed=rnorm(6),thu=rnorm(6),fri=rnorm(6))
week2 = data.frame(mon=rnorm(6),tue=rnorm(6),wed=rnorm(6),thu=rnorm(6),fri=rnorm(6))
week3 = data.frame(mon=rnorm(6),tue=rnorm(6),wed=rnorm(6),thu=rnorm(6),fri=rnorm(6))
week4 = data.frame(mon=rnorm(6),tue=rnorm(6),wed=rnorm(6),thu=rnorm(6),fri=rnorm(6))
week1=week1+15;week2=week2+15;week3=week3+15;week4=week4+15
vstat(week1)
vstat(week1,week2,week3,week4)