Letters of the Greek Alphabet and
Some of Their Statistical Uses

Letters of the Greek alphabet are often used in statistical notation. One very common use is to represent an unknown parameter of a probability distribution. (In that case an estimate of the parameter is sometimes denoted by the same Greek letter with a "hat" (^) above it, or by the corresponding Latin letter.)

The table below shows all 24 letters of the Greek alphabet in their alphabetical order. Both capital/ upper-case (UC) and small/ lower-case (LC) forms are shown, along with letter names and notes on some statistical uses. A few alternate forms of Greek letters that are almost never used in statistics are omitted. Many textbook authors invent their own uses for Greek letters; we show only uses that are somewhat standard.

Notes on pronunciation: In the US, Greek letters whose names end in i may be pronounced either with a long-i sound, or (except for pi and chi) with a long-e sound. Thus, phi (f) can sound like the beginning of "final" or like "fee"; but pi (p) sounds like "pie" and never like "pea." The ch in chi sounds like the ch in "chemistry," and, among knowledgeable statisticians, almost never like ch in "church." These conventions of pronunciation among US statisticians have little to do with authentic Greek pronunciation, either ancient or modern.

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