His 1983 book titled " Limited Dependent and Qualitative Variables in Econometrics " is now regarded as a classic and seminal text for advanced studies in econometrics.
12.
4 . " Representations of categories " of qualitative variables as in MCA ( a category lies at the centroid of the individuals who possess it ).
13.
With the two qualitative variables being gender and marital status and with the quantitative explanator being years of education, a regression that is purely linear in the explanators would be
14.
Roughly, we can say that FAMD works as a principal components analysis ( PCA ) for quantitative variables and as a multiple correspondence analysis ( MCA ) for qualitative variables.
15.
The core of MFA is based on a factorial analysis ( PCA in the case of quantitative variables, MCA in the case of qualitative variables ) in which the variables are weighted.
16.
For example, in a regression involving determination of wages, if two qualitative variables are considered, namely, gender and marital status, there could be an interaction between marital status and gender.
17.
The coordinate of qualitative variable j along axis s is equal to squared correlation ratio between the variable j and the factor of rank s ( denoted \ eta ^ 2 ( j, s ) ).
18.
For example, an experiment on baking bread could estimate the difference in the responses associated with quantitative variables, such as the ratio of water to flour, and with qualitative variables, such as strains of yeast.
19.
Thus, if more than one qualitative variable is included in the regression, it is important to note that the omitted category should be chosen as the benchmark category and all comparisons will be made in relation to that category.
20.
The remuneration gap is captured through a hard data indicator ( ratio of estimated female-to-male earned income ) and a qualitative variable calculated through the World Economic Forum s Executive Opinion Survey ( wage equality for similar work ).
