See attached

a)
β2 and β3is viewed as variable, because it varies on the dataset .
b)
and is viewed as variable, because it varies on the dataset used for the estimation .
c)
An estimator is said to be unbiased when the expected value is equal to the parameter.
d)
i)
If the random mistakes in the process are not regularly distributed, any conclusions drawn about the process may be inaccurate. If the real distribution of the random errors is such that the scatter in the...