Home ❯ All Definitions ❯ Probability & Statistics Definitions

# Probability & Statistics Definitions

Browse our growing collection of probability & statistics definitions:

#### Average

An average is a single number taken as representative of a list of numbers. Different concepts of average are used in different contexts.

#### Chi (Χ, χ)

Chi (Χ, χ) is the 22nd letter of the Greek alphabet, used to represent the ch sound (as in Scottish loch or German Bauch) in Ancient and Modern Greek. In the s…

#### Deciles

A decile is any of the nine values that divide the sorted data into ten equal parts, so that each part represents one tenth of the sample or population. A deci…

#### Event

An event is a certain subset of a probability space. Events are therefore collections of outcomes on which probabilities have been assigned.

#### High Quartile

The high quartile given a set of data, is a number for which 75% of the data is less than that number. The high quartile is the same as the median of the part…

#### Higher Quartile

The higher quartile given a set of data, is a number for which 75% of the data is less than that number. The higher quartile is the same as the median of the …

#### Impossible Event

A impossible event is an event which has zero probability of occurring.

#### Mu (Μ, μ)

Mu (Μ, μ) or my is the 12th letter of the Greek alphabet. In the system of Greek numerals it has a value of 40.

#### Pi (Π, π)

Pi (Π, π) is the sixteenth letter of the Greek alphabet, representing the sound [p]. In the system of Greek numerals it has a value of 80.

#### Q1

The Q1 given a set of data, is a number for which 25% of the data is less than that number. The Q1 is the same as the median of the part of the data which is …

#### Q3

The Q3 given a set of data, is a number for which 75% of the data is less than that number. The Q3 is the same as the median of the part of the data which is …

#### Sigma (Σ, σ)

Sigma (Σ, σ) is the eighteenth letter of the Greek alphabet. In the system of Greek numerals, it has a value of 200. In general mathematics, uppercase Σ i…

#### Theta (Θ, θ)

Theta (Θ, θ) is the eighth letter of the Greek alphabet, derived from the Phoenician letter Teth. In the system of Greek numerals it has the value 9.

#### Third Quartile

The third quartile given a set of data, is a number for which 75% of the data is less than that number. The third quartile is the same as the median of the pa…

#### Upper Quartile

The upper quartile given a set of data, is a number for which 75% of the data is less than that number. The upper quartile is the same as the median of the pa…

#### Weighted Average

The weighted average or weighted arithmetic mean is similar to an ordinary arithmetic mean (the most common type of average), except that instead it is used in…