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S uppose you survey students in your class and discover that a higher proportion of students who smoke received a final grade of A than do students who do not smoke. Possible data are displayed in Table 1: 50 percent of the 10 smokers received an A, and only 40 percent of the five nonsmokers received an A. Puzzled by the seeming implication that smoking(More)
The primary aim of this paper is to show how graphical models can be used as a mathematical language for integrating statistical and subject-matter information. In particular, the paper develops a principled, nonparametric framework for causal inference, in which diagrams are queried to determine if the assumptions available are suucient for identifying(More)
The direct effect of one event on another can be defined and measured by holding constant all intermediate variables between the two. Indirect effects present conceptual and prac­ tical difficulties (in nonlinear models), be­ cause they cannot be isolated by holding cer­ tain variables constant. This paper presents a new way of defining the effect transmit­(More)