Suppose You Estimate the Sample Multiple Linear Regression Function
What Is the Estimated Marginal Effect of X₁? X₂

Essay

Suppose you estimate the sample multiple linear regression function $\hat { y } _ { i } = \hat { \beta } _ { 0 } + \hat { \beta } _ { 1 } x _ { 1 i } + \hat { \beta } _ { 2 } x _ { 2 i } + \hat { \beta } _ { 3 } x _ { 1 i } \cdot x _ { 2 i }$
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What is the estimated marginal effect of x₁? x₂? Explain.