... considered a 40 per-cent fall.Because the midpoint method gives the same answer regardless of the direc-tion of change, it is often used when calculating the price elasticity of demand be-tween two ... together, such as comput-ers and software. In this case, the cross-price elasticity is negative, indicating thatan increase in the price of computers reduces the quantity of software demanded.QUICK ... affect attendance—weather, population, size of collection, and so forth—to isolate the effect of price. In the end, such data analysis would provide an estimate of the price elas-ticity of demand,...