The probability distribution function displays a range of values for any econometric model. The uncertainty that lies in the range of alpha/beta depends on several factors.
Depends on individuals, on time. However time is not solely a independent variable. It can be considered as a dependent, unidimensional variable.
Thus, the general rule is that any variable is to be considered dependent, never truly independent, as explained by the cause and effect theory.
To synthesize, we have modeled an abstract situation with respect to the given constraints.