For this question it is not necessary to run any regressions in Stata. Instead, consider the following regression model for a simple random sample of farmers: Yield Bo Rainfall + 2 Drought Tolerant Crops + u = These variables are defined as follows: Yield - The farm's annual agricultural yield (in dollars) Rainfall - Historical annual rainfall on the farm (in inches) Drought Tolerant Crops - A dummy variable indicating that the farm is growing at least one variety of drought tolerant crop Are either of our regressors endogenous? Explain your reasoning