Independent and identically distributed random variables

In probability theory and statistics, a sequence or other collection of random variables is independent and identically distributed (i.i.d.) if each random variable has the same probability distribution as the others and all are mutually independent.

The abbreviation i.i.d. is particularly common in statistics (often as iid, sometimes written IID), where observations in a sample are often assumed to be effectively i.i.d. for the purposes of statistical inference. The assumption (or requirement) that observations be i.i.d. tends to simplify the underlying mathematics of many statistical methods (see mathematical statistics and statistical theory). However, in practical applications of statistical modeling the assumption may or may not be realistic. To test how realistic the assumption is on a given data set, the autocorrelation can be computed, lag plots drawn or turning point test performed. The generalization of exchangeable random variables is often sufficient and more easily met.

IID (company)

IID, previously Internet Identity, is a privately held Internet security company based in Tacoma, Washington, USA. It primarily provides cyberthreat data, a platform to exchange cyberthreat data, and anti-phishing, malware and domain control security services to US federal government agencies, financial service firms, and e-commerce, social networking and Internet Service Provider(ISP) companies. Microsoft uses IID as a data feed for its anti-phishing software as well as a partner in their Domain Defense Program. Other customers include BECU (Boeing Employees’ Credit Union), Monster.com and Yakima Valley Credit Union.

History

IID was founded in 1996 providing outsourced domain management services. In 1997, the company claims to have discovered and disabled one of the earliest phishing attacks. Since then, IID’s business has revolved around protecting companies against cyber attacks. In 2013, IID accepted its first round of institutional funding for $8 million from Bessemer Venture Partners.

IID (disambiguation)

IID may refer to: