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ISO 3166-1 ( Codes for the representation of names of countries and their subdivisions – Part 1: Country codes) is a standard defining codes for the names of countries, dependent territories, and special areas of geographical interest. It is the first part of the ISO 3166 standard published by the International Organization for Standardization .
A plot of normal distribution (or bell-shaped curve) where each band has a width of 1 standard deviation – See also: 68–95–99.7 rule. Cumulative probability of a normal distribution with expected value 0 and standard deviation 1 In statistics, the standard deviation is a measure of the amount of variation of a random variable expected about its mean.
Probability theory. In probability theory and statistics, a normal distribution or Gaussian distribution is a type of continuous probability distribution for a real-valued random variable. The general form of its probability density function is. The parameter is the mean or expectation of the distribution (and also its median and mode ), while ...
ISO 639 is a standardized nomenclature used to classify languages. Each language is assigned a two-letter (set 1) and three-letter lowercase abbreviation (sets 2–5). Part 1 of the standard, ISO 639-1 defines the two-letter codes, and Part 3 (2007), ISO 639-3, defines the three-letter codes, aiming to cover all known natural languages, largely superseding the ISO 639-2 three-letter code standard.
Example of samples from two populations with the same mean but different variances. The red population has mean 100 and variance 100 (SD=10) while the blue population has mean 100 and variance 2500 (SD=50) where SD stands for Standard Deviation. In probability theory and statistics, variance is the expected value of the squared deviation from the mean of a random variable.
In probability theory and statistics, the chi-squared distribution (also chi-square or -distribution) with degrees of freedom is the distribution of a sum of the squares of independent standard normal random variables. The chi-squared distribution is a special case of the gamma distribution and is one of the most widely used probability distributions in inferential statistics, notably in ...
www .iso .org. [2] The International Organization for Standardization ( ISO / ˈaɪsoʊ / [3]) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. [4] Membership requirements are given in Article 3 of the ISO Statutes.
