In bio-statistics there is a consistent pattern in perinatal data: Among babies born with low birth-weight, infants born to smokers have lower first-year mortality than those born to non-smokers. At first (or even second) blush, it might appear that smoking is beneficial to underweight infants. …

Introduction Data.tableis a powerful modern update of the venerable old data.frame. Under the hood, the package has been tuned for blazing speed and minimal memory usage with a syntax that is sleek and spare. …