Parameter Estimation and Evaluation Maximum Likelihood Estimation Maximum Likelihood Estimation MLE may not be unique.Given an observed data set x",MLE may be obtained at more than one point in Thus,multiple solutions for MLE are possible. ●The maximum is obtained over parameter space曰，where may be subject to some restriction.For example, when estimating a Generalized AutoRegressive Condi- tional Heteroskedasticity (GARCH)model (Bollerslev 1986),0 may be subject to some restrictions to ensure that the conditional variance is always nonnegative. Parameter Estimation and Evaluation Introduction to Statistics and Econometrics April 21,2020 23/207Parameter Estimation and Evaluation Parameter Estimation and Evaluation Introduction to Statistics and Econometrics April 21, 2020 23/207 Maximum Likelihood Estimation Maximum Likelihood Estimation