Probability theory and statistics have some commonly used conventions, in addition to standard mathematical notation and mathematical symbols.
Probability theory 
- Greek letters (e.g. θ, β) are commonly used to denote unknown parameters (population parameters).
- An estimate of a parameter is often denoted by placing a caret over the corresponding symbol, e.g. , pronounced "theta hat".
- Some commonly used symbols for sample statistics are given below:
- Some commonly used symbols for population parameters are given below:
- the population mean μ,
- the population variance σ2,
- the population correlation ρ,
- the population cumulants κr.
- The arithmetic mean of a set of numbers x1, x2, ..., xn is denoted by , pronounced "x bar".
Critical values 
The α-level upper critical value of a probability distribution is the value exceeded with probability α, that is, the value xα such that F(xα) = 1 − α where F is the cumulative distribution function. There are standard notations for the upper critical values of some commonly used distributions in statistics:
Linear algebra 
- Matrices are usually denoted by boldface capital letters, e.g. A.
- Column vectors are usually denoted by boldface lower case letters, e.g. x.
- The transpose operator is denoted by either a superscript T (e.g. AT) or a prime symbol (e.g. A′).
- A row vector is written as the transpose of a column vector, e.g. xT or x′.
Common abbreviations include:
See also 
- Halperin, Max; Hartley, H. O.; Hoel, P. G. (1965), "Recommended Standards for Statistical Symbols and Notation. COPSS Committee on Symbols and Notation", The American Statistician 19 (3): 12–14, doi:10.2307/2681417, JSTOR 2681417
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