Background Let Sn=X1+…+Xn be the sum of the first n of them. Limit theorems are mostly concerned with the properties of S and related random variables as n becomes very large.Background ◼ Let 𝑆𝑛 = 𝑋1 + ⋯ + 𝑋𝑛 be the sum of the first 𝑛 of them. ◼ Limit theorems are mostly concerned with the properties of 𝑆𝑛 and related random variables as 𝑛 becomes very large