The theory underlying AP Statistics and Business Statistics courses is given with most formula derivations and proofs. The difficulty level gradually increases from graphical and numerical examples to full proofs supporting the one-way and two-way ANOVA. The material is carefully selected to provide statistical prerequisites to Econometrics taught at the University of London. The exposition is illustrated with more than 40 tables and more than 30 figures. The book has several innovative features: a) methodical recommendations to students, b) Monte Carlo simulations in Excel, c) the Markovitz portfolio theory, d) a separate chapter on links to Econometrics, and e) usage of statistical functions in Excel and Mathematica instead of statistical tables.