Consider the Following Panel Data Regression with a Single Explanatory $$Y _ { i t } = \beta _ { 0 } + \beta _ { 1 } X _ { i t } + u _ { i t } .$$

Essay

Consider the following panel data regression with a single explanatory variable $$Y _ { i t } = \beta _ { 0 } + \beta _ { 1 } X _ { i t } + u _ { i t } .$$ In each of the examples below, you will be adding entity and time fixed effects.Indicate
the total number of coefficients that need to be estimated.
(a)The effect of beer taxes on the fatality rate, annual data, 1982-1988, nine U.S.regions
(New England, Pacific, Mid-Atlantic, East North Central, etc.).