STATISTICAL COMMENTS (Simpson's Paradox) While most of the five chapters are about probability and probability distributions, from time to we will mention certain statistical concepts, As an illustration, the relative frequency, f/n, is called a statistic and is used to estimate a probability p, which is usually unknown. For example, if a major league batter gets f=152 hits in n=500 official at bats during the season, then the relative frequency f/n=0.304 is an estimate of his probability of getting a hit and is called his batting average for that season.