Briefly Identify the Following in Words or Equations as Appropriate $\ln Y = \beta _ { 0 } + \beta _ { 1 } \ln X + \varepsilon$

Essay

Briefly identify the following in words or equations as appropriate:
(a) The major consequence of including an irrelevant variable in a regression equation.
(b) Four valid criteria for determining whether a given variable belongs in an equation.
(c) The problem with sequential specification searches.
(d) The elasticity of Y with respect to X in:
$\ln Y = \beta _ { 0 } + \beta _ { 1 } \ln X + \varepsilon$ (e) The sign of the bias on the coefficient of age caused by omitting experience in an equation explaining the salaries of various workers.