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The Tobit model is a statistical model proposed by James Tobin (1958) to describe the relationship between a non-negative dependent variable and an independent variable (or vector) . The term ''Tobit'' was derived from Tobin's name by truncating and adding ''-it'' by analogy with the probit model.〔''International Encyclopedia of the Social Sciences'' (2008)〕 The model supposes that there is a latent (i.e. unobservable) variable . This variable linearly depends on via a parameter (vector) which determines the relationship between the independent variable (or vector) and the latent variable (just as in a linear model). In addition, there is a normally distributed error term to capture random influences on this relationship. The observable variable is defined to be equal to the latent variable whenever the latent variable is above zero and zero otherwise. : where is a latent variable: : ==Consistency== If the relationship parameter is estimated by regressing the observed on , the resulting ordinary least squares regression estimator is inconsistent. It will yield a downwards-biased estimate of the slope coefficient and an upward-biased estimate of the intercept. Takeshi Amemiya (1973) has proven that the maximum likelihood estimator suggested by Tobin for this model is consistent. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Tobit model」の詳細全文を読む スポンサード リンク
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