Introduction

Statistical learning plays a key role in many areas of science, finance and industry. Here are some examples of learning problems: • Predict whether a patient, hospitalized due to a heart attack, will have a second heart attack. The prediction is to be based on demographic, diet and clinical measurements for that patient.• Predict the price of a stock in 6 months from now, on the basis of company performance measures and economic data.• Identify the numbers in a handwritten ZIP code, from a digitized image.• Estimate the amount of glucose in the blood of a diabetic person, from the infrared absorption spectrum of that person’s blood.• Identify the risk factors for prostate cancer, based on clinical and demographic variables.