This manual is aimed at students in higher education.This manual has a unifying concept: it's a continuum whose different parts refer to each other. It is not intended to be exhaustive, but rather pedagogical and explanatory, so as to make the essential clear and open up a wider field.Our main objectives are to- Consolidate knowledge already acquired;- Motivate students by enabling them to apply their knowledge in concrete situations;- To help students understand the value and limits of the information available for decision-making. The manual comprises a number of chapters that follow the same approach.