[讨论]Stata: Resources For Learning Stata

[下载]REGRESSION MODELS FOR CATEGORICAL DEPENDENT VARIABLES USING STATA

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[下载]David Kenny.Correlation and Causality

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[讨论]Stata: Resources For Learning Stata

SPSS Programming and Data Management: A Guide for SPSS and SAS Users, Second Edition documents the wealth of functionality beneath the SPSS user interface. It includes detailed examples of command syntax, the macro facility, scripting, and the output management system. The accompanying CD-ROM includes the command and data files used in the book. The book also contains a chapter for SAS users, showing equivalent SPSS code for many common data management tasks. With knowledge gained from this book, you will be able to use the many tools available within SPSS to import data from almost any source, clean it, transform it, merge it with other data, and get it into the condition required to produce reliable models and informative results.

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[讨论]Stata: Resources For Learning Stata
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Question: What does Exogenous Variable Means?

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Exogenous (or exogeneous) (from the Greek words "exo" and "gen", meaning "outside" and "production") refers to an action or object coming from outside a system. It is the opposite of endogenous, something generated from within the system.

• In an economic model, an exogenous change is one that comes from outside the model and is unexplained by the model. For example, in the simple supply and demand model, a change in consumer tastes or preferences is unexplained by the model and also leads to endogenous changes in demand that lead to changes in the equilibrium price. Put another way, an exogenous change involves an alteration of a variable that is autonomous, i.e., unaffected by the workings of the model.

• In biology, "exogenous" refers to an action or object coming from the outside of a system. For example, an exogenous contrast agent in medical imaging refers to a liquid injected IV in the patient that enhances visibility of a pathology, such as a tumor.

• In biology, an exogenous factor is any material that is present and active in an individual organism or living cell but that originated outside of that organism, as opposed to an endogenous factor.
  
  • Exogenous factors in medicine include both pathogens and therapeutics.
    
  • DNA introduced to cells via transfection or viral infection (transduction) is an exogenous factor.
    
  • Carcinogens are exogenous factors.

• The word exogenous is also used in geology. Exogenous processes are all taking place at the outside of the Earth and all the other planets. Weathering, erosion, transportation and sedimentation are the main exogenous processes.

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Endogenous

• In biology endogenous substances are those that originate from within an organism, tissue or cell [1]. In biological systems endogeneity (biology) refers to recipient of DNA (usually in prokaryotes). However, due to homeostasis, discerning between internal and external influences is often difficult.

• In an economic model, an endogenous change is one that comes from inside the model and is explained by the model itself.

• In geology the word endogenous refers to all processes that take place inside the Earth and all other planets. They make the continents move, push the mountains up, trigger earthquakes and vulcanism. Endogenous processes are driven by the warmth which is produced in the core of the Earth by radioactivity and gravity.

• In psychology an emotion or behaviour is endogenous if it is spontaneously generated from an individual's internal state.

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Exogenous variable:

A factor in a causal model or causal system whose value is independent from the states of other variables in the system; a factor whose value is determined by factors or variables outside the causal system under study. For example, rainfall is exogenous to the causal system constituting the process of farming and crop output. There are causal factors that determine the level of rainfall — so rainfall is endogenous to a weather model — but these factors are not themselves part of the causal model we use to explain the level of crop output. As with endogenous variables, the status of the variable is relative to the specification of a particular model and causal relations among the independent variables. An exogenous variable is by definition one whose value is wholly causally independent from other variables in the system. So the category of “ exogenous” variable is contrasted to those of “ purely endogenous” and “ partially endogenous” variables. A variable can be made endogenous by incorporating additional factors and causal relations into the model. There are causal and statistical interpretations of exogeneity. The causal interpretation is primary, and defines exogeneity in terms of the factor’s causal independence from the other variables included in the model. The statistical or econometric concept emphasizes non- correlation between the exogenous variable and the other independent variables included in the model. If xj is exogenous to a matrix of independent variables X ( excluding xj), then if we perform a regression of xj against X ( excluding xj), we should expect coefficients of 0 for each variable in X ( excluding xj). Normal regression models assume that all the independent variables are exogenous.

Engle, R. F., D. F. Hendry, and J. F. Richard. 1983. Exogeneity. Econometrica 51: 277- 304.

Pearl, Judea. 2000. Causality: models, reasoning, and inference. Cambridge: Cambridge University Press.

Woodward, James. 1995. Causation and Explanation in Econometrics. In On the Reliability of Economic Models: Essays in the Philosophy of Economics, edited by D. Little. Bostn: Kluwer Academic Publishers.

Encyclopedia of Social Science Research Methods, edited by Michael Lewis- Beck ( University of Iowa), Alan Bryman ( Loughborough University), and Tim Futing Liao. Sage Publications.

An exogenous variable is an economic variable which is independent of the relationships determining the equilibrium levels, but nonetheless affects the equilibrium