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 the Marshallian (10[1])form of this quantity to its Hicksian form by accounting for (10[1])the substitution (10[1])and income effects. The cross elasticity of this quantity measures its sensitivity to changes in a different good’s price. For Veblen (10[1])goods, this quantity [emphasize] increases as price (10[1])increases, often due to the value of those goods as status symbols. For 10 points, what quantity is defined as consumers’ willingness and ability to buy a certain good? ■END■