CS1 Actuarial Statistics
Distributions, inference, credibility and the central limit theorem: interactive statistics plus the tables and cheat sheet CS1 leans on.
Interactive tools
Statistical tables
Normal, Student's t, chi-squared and F: the classic printed tables plus exact calculators and shape plots for any parameters, inverse percentiles and two-sided critical values. Handy for CS1, CS2 and any stats exam.
Credibility theory calculator
Edit a claims grid by risk and year and get the EBCT Model 1 variance components, the credibility factor Z and every risk's blended premium, working shown. CS1, with a test-yourself mode and worked solutions.
Central limit theorem demo
Pick a lopsided parent distribution, slide the sample size, and watch the histogram of sample means squeeze into the exact normal curve the CLT predicts. CS1 and any stats exam.
Bayesian conjugate priors
Beta-Binomial and Gamma-Poisson updating on sliders: prior, likelihood and posterior drawn live, with the posterior mean decomposed into its credibility weights. CS1.
Hypothesis testing & power
Type I and Type II errors shaded under the null and true sampling distributions, with the power curve against sample size. The trade-off, watched rather than defined. CS1.
Confidence interval simulator
One hundred samples, one hundred intervals, one fixed true mean: misses in red, coverage counted, and a t toggle for estimated sigma. The classic misconception, cured. CS1.
Linear regression playground
Drag points and the least squares line chases them, residuals hanging in gold, with b, a, r and R squared recomputed live from Sxx, Sxy and Syy. CS1 and any stats course, with a test-yourself mode and worked solutions.
Reference sheets
Probability distributions cheat sheet
Every CS1 distribution on one page: what it models, density, mean, variance and generating function, from Bernoulli to the F distribution. Assumed knowledge for CS2.
CS1 formula cheat sheet
Distribution moments, the CLT and sampling distributions, maximum likelihood and the Cramér-Rao bound, regression, Bayesian methods, credibility and GLMs: the CS1 core rendered properly on one page. CS2 assumes all of it.