You try to explain the number of IBM shares traded in the stock market per day in 2005. As an independent variable you choose the closing price of the share. This is an example of
A. simultaneous causality.
B. invalid inference due to a small sample size.
C. sample selection bias since you should analyze more than one stock.
D. a situation where homoskedasticity-only standard errors should be used since you only analyze one company.
查看答案
Threats to in internal validity lead to
A. perfect multicollinearity
B. the inability to transfer data sets into your statistical package
C. failures of one or more of the least squares assumptions
D. a false generalization to the population of interest
The true causal effect might not be the same in the population studied and the population of interest because
A. of differences in characteristics of the population
B. of geographical differences
C. the study is out of date
D. all of the above
Consider the following regression model: log(y) = β0 + β1x1 + β2x12 + β3x3 + u. This model will suffer from functional form misspecification if _____.
A. β0 is omitted from the model
B. u is heteroskedastic
C. x12 is omitted from the model
D. x3 is a binary variable
A regression model suffers from functional form misspecification if _____.
A. a key variable is binary.
B. the dependent variable is binary.
C. an interaction term is omitted.
D. the coefficient of a key variable is zero.
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