This document summarizes four examples from a lecture on quantitative analysis for business. The first example calculates average cost, cost deviation, covariance between cost and age, and cost increase per year for machine maintenance. The second example derives cost estimation equations for three machines that extrude plastic tubes based on tube length and setup costs. The third example estimates a linear model and price point to meet a weekly demand of 500 units based on demand at two given price points. The fourth example is not summarized.