Beef and steak are elastic since they have substitutes and are not necessities. Public transportation, gasoline, and housing are inelastic because they are necessities with limited alternatives. Pencils are also inelastic due to their low cost. If the PED is 1.5 (elastic), lowering the price increases revenue as demand responds significantly. If the PED is 0.8 (inelastic), raising the price increases revenue since demand is less responsive.