The Rotterdam model can be used to estimate one form of this quantity, for which Richard Stone was the first to empirically derive a linear expenditure system. For a firm in a perfectly competitive market, this quantity is infinitely elastic. The Slutsky equation relates (-5[1])the Marshallian form (10[1])of this quantity (10[2])to its Hicksian form by accounting for the substitution and income effects. (10[1])The cross elasticity of this quantity measures its sensitivity (10[1])to changes in a different good’s price. For Veblen goods, this quantity [emphasize] increases as price increases, often due to the value (-5[1])of those (10[1])goods as status (10[1])symbols. For 10 points, what quantity is defined as consumers’ willingness and ability to buy a certain (10[1])good? (10[1])■END■