Frequency (statistics)

Frequency has two meanings:

• Everyday meaning: The term frequency is understood in everyday language, the number of events within a period. For periodic processes this size can also be called frequency. In everyday life loud questions on the frequency: "How often / How many times in their lives ... " or "How often / How many times a week ... ".

• Statistical significance: In statistics, the word frequency is applied not only to events but also to objects. So there is the " relative frequency of women of a City", which seems unusual in everyday language.

Types of statistical frequency term

When specifying the statistical frequency we distinguish different forms:

• Absolute frequency: number, result of the counting
• Relative frequency: number of elements of a subset relative to the base amount

• Cumulative frequency (also cumulative frequency ): For an ordinal, or scale the scaled characteristic manifestations ai be the size ( in ascending order ) after sorted. The cumulative frequency of a feature, the sum of all frequencies up to and including the respective characteristic value ai (see figure). Both absolute and relative frequencies can be accumulated.

In addition, a distinction is made between the expected frequency and observed frequency. The graphical representation of the frequency is the frequency distribution.

The combination of the terms occasionally occurs: for example, cumulative relative frequencies, cumulative absolute frequencies, expected absolute frequency, etc.

Word origin

The original meanings of the following similar words refer the word frequency depending on the context in different meanings:

• The "pure" number and thus on the absolute frequency as a result of the counting,
• On the number of objects within a given space, than density, such as population density, as absolute frequency of inhabitants of a city,
• On the number of events within a time period: a frequency
• The number of elements of a subset relative to the base amount as a relative frequency.

The adjective often still meant in the 16th century actually " heaps ", since the 18th century "often". It means something like " in large numbers occurring, repeated ereignend " or " numerous in large numbers, in large quantities ." Heaps also means " in piles, in masses " or " flock en masse ".

The same applies to the word accumulation, which can mean as much as " storage in large quantities ", but also "collection, frequent occurrence (of phenomena, events ) ." The word clustering can also refer to the " act of Häufens " as of earth or the accumulation of business, as well as the word ridging.

The word frequency is also sometimes used in the sense of frequency, ie spatial or temporal density of occurrence. To refer the Brockhaus encyclopedia in the word frequency in the context of linguistics at the lemma frequency. Here is found that the word frequency in Latin stands for frequency. The frequency of the word refers to the frequency with which a word in a given text or a text corpus occur. Because of the frequency distributions frequency dictionaries can be created that provide information about the frequency of use of a word.

The word frequency is technical language in the 17th century, borrowed from the Latin " frequentia " in the meaning " frequency ". This is an abstraction to Latin " Frequentis " = "often" and related fracīare with Latin " cram " for.

" In addition, frequency number or frequency rate is the number that indicates how often an event occurs within a time period or a certain phenomenon repeats itself. "

Specific examples of the concept of frequency

Examples of relative frequencies:

• Under natural frequency is defined as the relative frequency of chemical substances.
• The frequency of errors is a special field of observation to measurement errors.