triangle.test: Make a Triangle test for a set of products
Description
Make a Triangle test for a set of products.
Usage
triangle.test (design, answer, preference = NULL)
Value
Returns a list of matrices. Each matrix give the reult for all the pair of products:
nb.comp
a matrix with the number of comparisons done for each pair of products;
nb.ident
a matrix with the number of panelists who indicate the odd product for each pair of products;
p.value
a matrix with the p-value of the Triangle tests for each pair of products;
nb.recognition
estimation of the panelists who really perceived the difference between two product, for each pair of product;
maxML
Maximum Likelihood of the estimation of the number of panelists who really perceive the difference between the products;
confusion
estimation of the percentage of panelists who do not perceived the difference between two product, for each pair of product;
minimum
minimum of panelists who should detect the odd product to can say that panelists perceive the difference between the products, for each pair of products;
preference
number of times that product of row i is prefered that product in column j for the panelists who find the odd product.
Arguments
design
a data.frame corresponding to the design use to make the Triangle test (typically the ouput of the function triangle.design
answer
a vector of the answers of all the panelists; all the answer should be "X", "Y" or "Z"
preference
a vector of the preference of the panelists; all the answer should be "X", "Y" or "Z" (by default, there preference are not taken into account)
Author
Francois Husson
Details
Triangle test: panelists receive three coded samples. They are told that two of the sample are the same and one is different.
Panelists are asked to identify the odd sample.