generally unobserved
1Middle Chinese — 中古漢語 Spoken in China Region Medieval China Extinct Evolved into Proto Mandarin and other Chinese dialects apart from Min …
2Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity. Computer scientist Manindra Agrawal of the… …
3Discrete choice — In economics, discrete choice problems involve choices between two or more discrete alternatives, such as entering or not entering the labor market, or choosing between modes of transport. Such choices contrast with standard consumption models in …
4Instrumental variable — In statistics, econometrics, and related disciplines, the method of instrumental variables (IV) is used to estimate causal relationships when controlled experiments are not feasible. Statistically, IV methods allow consistent estimation when the… …
5comet — cometary /kom i ter ee/, cometic /keuh met ik/, cometical, adj. cometlike, adj. /kom it/, n. Astron. a celestial body moving about the sun, usually in a highly eccentric orbit, consisting of a central mass surrounded by an envelope of dust and… …
6Principal-agent problem — In political science and economics, the principal agent problem or agency dilemma treats the difficulties that arise under conditions of incomplete and asymmetric information when a principal hires an agent. Various mechanisms may be used to try… …
7Life Sciences — ▪ 2009 Introduction Zoology In 2008 several zoological studies provided new insights into how species life history traits (such as the timing of reproduction or the length of life of adult individuals) are derived in part as responses to… …
8Faster-than-light — (also superluminal or FTL) communications and travel refer to the propagation of information or matter faster than the speed of light. Science fiction style space travel, dubbed true FTL, defies known physics.Under the special theory of… …
9108th Air Refueling Wing — Infobox Military Unit unit name= 108th Air Refueling Wing caption= 108th Air Refueling Wing emblem dates= 1952 Present country= United States allegiance= branch= United States Air Force type= Air Refueling role= Combat Support size= command… …
10Heckman correction — The Heckman correction (the two stage method, Heckman s lambda or the Heckit method) is any of a number of related statistical methods developed by James Heckman in 1976 through 1979 which allow the researcher to correct for selection bias.… …
