In the following chapters a great deal of use will be made of symbols in both the text and in algebraic expressions. Some of these are standard algebraic symbols, but many more have special meanings within a sampling or statistical context. Unfortunately, statistical symbology is not standard and considerable variation is encountered in the literature. In recent years the situation has improved considerably and it is probable that standardization will eventually be achieved. An attempt will be made in this text to remain in the mainstream of current thought in this matter, but where it appears that understanding would be facilitated by modifications they will be made.