True, False, Uncertain. Explain your answer. Credit entirely depends on the explanation.

i. General concepts

1. If data are generated by a nonergodic process, then the parameters of the process generating the data are not identified.

2. If the parameters of a model are partially identified, but not identified, the model will not be useful for policy evaluation.

3. If the process generating the data under study is nonstationary, then statistical models cannot be used to analyze the properties of the process.

4. Models assuming second order stationary of time series are appropriate for time series data from Russia for 1991 to 2015.