Econ120BCh9

Econ120BCh9 - Chapter 9 Answers 9.1, 9.2, 9.3, 9.7, 9.8,...

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Chapter 9 Answers 9.1, 9.2, 9.3, 9.7, 9.8, 9.10 1. As explained in the text, potential threats to external validity arise from differences between the population and setting studied and the population and setting of interest. The statistical results based on New York in the 1970’s are likely to apply to Boston in the 1970’s but not to Los Angeles in the 1970’s. In 1970, New York and Boston had large and widely used public transportation systems. Attitudes about smoking were roughly the same in New York and Boston in the 1970s. In contrast, Los Angeles had a considerably smaller public transportation system in 1970. Most residents of Los Angeles relied on their cars to commute to work, school, and so forth. The results from New York in the 1970’s are unlikely to apply to New York in 2002. Attitudes towards smoking changed significantly from 1970 to 2002. 2. (a) When Y i is measured with error, we have or Substituting the 2nd equation into the regression model  , ii i YYw  . ii i  01 i YX i i u gives  , i Xu Yw i i w or Thus .
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This note was uploaded on 09/19/2009 for the course ECON 656820 taught by Professor Megerdichian during the Summer '09 term at UCSD.

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Econ120BCh9 - Chapter 9 Answers 9.1, 9.2, 9.3, 9.7, 9.8,...

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