ardi: Automatic Research of DIvergences between scores

Description

Spot the most singular or particular data with respect to all descriptors and to two qualitative variables and all their possible categories combinations. Computes the highest differences between all the categories of the variables product, panelist and all their possible combinations, with respect to a set of quantitative variables (the sensory descriptors).

Usage

ardi(donnee,col.p,col.j,firstvar,lastvar=ncol(donnee),nbval=10,center=TRUE,scale=FALSE)

Arguments

donnee

a data frame made up of at least two qualitative variables (product, panelist) and a set of quantitative variables (sensory descriptors)

col.p

the position of the product variable

col.j

the position of the panelist variable

firstvar

the position of the first sensory descriptor

lastvar

the position of the last sensory descriptor (by default the last column of donnee)

nbval

the number of highest divergences to be displayed

center

by default, data are mean centered by panelist

scale

by default, data are not scaled by panelist

Value

A list containing the following elements:
taba data frame (descriptors are mean centered per panelist and scaled to unit variance)
panelista data frame, by default the 10 highest divergences between panelists according to the sensory descriptors
producta data frame, by default the 10 highest divergences between products according to the sensory descriptors
combinationa data frame, by default the 10 highest divergences between panelists and products according to the sensory descriptors

Details

Step 1 For each quantitative variable, means by all the possible combinations (panelist,product) are computed. Step 2 Then, data are mean centered and scaled to unit variance by descriptor and the divergence corresponds to the absolute value of the entries. Step 3 Means on divergences are computed by products or by panelists and then sorted.

Examples

Run this code

data(chocolates)
ardi(chocolates,col.p=4,col.j=1,firstvar=5)

## In the case where there's one particular variable of interest
ardi(chocolates,col.p=4,col.j=1,firstvar=7,lastvar=7)