It all starts here. Two categories determine what the menu will offer you next.
The nature of the variables:
- Quantitative : a measurement, a number for which an average makes sense: an elevation, a pressure, a time
- Qualitative : one category: one machine, one operator, one type of defect, one OK/KO verdict.
The role of variables:
- Y is what we observe, the quantity we are interested in; ;
- X That might explain it.
💡 Selecting a single Y describes a population. Specifying an X as well raises a question of relationship: Does Y depend on X?
This is the part that unlocks cloud computing, multivariate analysis, and regression analysis.