Chapter 2 · Test 1
Sets, Numbers & Functions
Set operations, number properties, point sets, functions, and convexity.
What you will learn
- Compute a set intersection
- Compute a complement
- Calculate a convex combination
Reasoning habits that help
- Intersection means AND: an element must satisfy membership in both sets.
- A complement is meaningless until the universal set has been specified.
- A convex combination uses nonnegative weights that add to one, placing the result between the original points.
Where economists use these methods
- Set intersections identify groups satisfying several conditions, such as workers who are both employed and insured.
- Complements describe populations outside a category, such as households that do not receive a particular benefit.
- Convex combinations represent diversified portfolios, probability mixtures, and feasible averages of economic choices.