I am having trouble beginning the below question.
Suppose that $Y_1, Y_2, Y_3$ are uncorrelated random variables with common variance $σ^2$ and expected values $2β_1 + 2β_2$, $β_1 −2β_2$, and $2β_1 −β_2$, respectively. let $y_1,y_2,$ and $y_3$ be the realisations of $y_1, y_2, y_3$.
b) Find the least squares estimates of $β_1$ and $β_2$.
I am unsure as to begin this as a simple linear regression problem or a multiple linear regression problem.
Do I start with $Y_i = β_1 + β_2X_i + e_i$
Or $Y_i = β_0 + β_1X_i + β_2X_i + e_i$