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Price Elasticity of Demand
What is Price Elasticity of Demand? The analysis of price elasticity of demand (PED or Ed ) is essential in marketing because it is an approach that allows setting the price of a product, knowing that the goal, at least in the mid-term, is to maximize the revenue generated by the product. The elasticity which concept is due to Alfred Marshall (1920) is defined as the relative variation of demand (or...
Product characterization
When to use product characterization Product characterization provides the XLSTAT users with a user-friendly analytical method that helps finding in a sensory study which descriptors are discriminating well a set of products. You can also identify which are the most important characteristics of each product. Computation for product characterization All computations are based on the analysis of variance...
Design of experiments for the analytic hierarchy process (DHP)
The principles of Analytic Hierarchy Process The principle of AHP method is to compare the solutions of a decision problem using on a set of criteria in order to deduce the best solution. The application of such method requires defining several numerical tables whose number can quickly increase according to the characteristics of the decision problem (number of criteria, of sub criteria, of alternatives...
Multidimensional tests (Mahalanobis, …)
What are multidimensional tests Multidimensional tests implemented in XLSTAT are used to compare samples described by several variables. Instead of comparing the average of two samples as with the Student t test, we compare here simultaneously for the same samples averages measured for several variables. Compared to a procedure that would involve as many Student t-tests as there are variables, the...
Statistical Power for linear regression
Statistical Power for linear regression XLSTAT-Pro offers a tool to apply a linear regression model. XLSTAT-Power estimates the power or calculates the necessary number of observations associated with variations of R ² in the framework of a linear regression. When testing a hypothesis using a statistical test, there are several decisions to take: The null hypothesis H0 and the alternative hypothesis...
TCATA
What is TCATA method? The TCATA method is a temporal extension of the CATA (Check-All-That-Apply) method developed by Castura et al (2015). This method describes the multidimensional sensory properties of products as they evolve over time. Selection and deselection of attributes are tracked continuously over time, allowing assessors to characterize the evolution of sensory changes in products. Graphical...
Heat map
What is a heat map in an OMICS context? While exploring individuals/features matrices in an OMICS framework, it is interesting to examine how correlated features (i.e. genes, proteins, metabolites) correspond to similar individuals (i.e. samples). For example, a cluster of diseased kidney tissue samples may be characterized by a high expression of a group of genes, compared to other samples. The heat...
Power for Sensory discrimination tests
Why should we compute the power of sensory discrimination tests? Experimental planning is a fundamental step for anyone who wants to ensure that the collected data will be usable under the best possible statistical conditions. There is no point in having products evaluated by a panel of subjects if they cannot then be compared under satisfactory statistical conditions. XLSTAT Power for Sensory discrimination...
Classification and regression trees
What are classification and regression trees Classification and regression trees are methods that deliver models that meet both explanatory and predictive goals. Two of the strengths of this method are on the one hand the simple graphical representation by trees, and on the other hand the compact format of the natural language rules. We distinguish the following two cases where these modeling techniques...
Grubbs' test for outliers
What is the Grubbs test Grubbs (1950, 1969, 1972) developed several tests in order to determine whether the greatest value or the lowest value (Grubbs test) are outliers, or, for the double Grubbs test, whether the two greatest values or the two lowest ones are outliers. This test assumes that the data corresponds to a sample extracted from a population that follows a normal distribution. Detecting...