The CS series builds the statistical and stochastic modelling skills that sit alongside CM’s financial mathematics. CS1 lays the statistical foundation — distributions, inference, regression, and Bayesian/credibility methods. CS2 then builds on CS1 to cover stochastic processes, survival modelling, time series, loss distributions, and a first introduction to machine learning. Together, these two subjects are what let an actuary move from “here’s a spreadsheet of past claims” to “here’s a defensible statistical model of future risk” — skills used daily in pricing, reserving, and experience analysis.