4. If the sign of Bo, is positive, does this mean the omitted variable causes us to overstate of understate the effect of an increase in price when estimating Bon? 5. If you know that Slabor = -5, cov(pou, labor) = 2.50, and var(p. ) = 9.30, what is the omitted variable bias equal to? 6. Instead, assume that there is no relationship between pan and labor, or cov(pag, labor) = 0. What is the omitted variable bias equal to? 7. If the number of firms that produce oil is a determinant of supply, is the variable producer,, which measure the number of oil producers in a state an irrelevant variable or an omitted variable in the oil supply regression