Discuss the eight demand states with respect to bifocal lenses for glasses.
Answer: Student answers may vary, but a possible answer includes the following: (1) negative demand—many people don't want to admit they need bifocals, (2) nonexistent demand—when bifocal lenses were first introduced, people didn't know they existed, (3) latent demand—before they were introduced, many people thought such a product would be nice, but didn't think it would ever exist, (4) declining demand—this will occur when something better and more convenient is invented, (5) irregular demand—the consumer perceives a need for eye care devices only periodically, possibly when they begin to have trouble with their vision, (6) full demand—the manufacturers of the lenses are making all they possibly can, (7) overfull demand—the manufacturers of the lenses can't make enough and inventories are low, and (8) unwholesome demand—seeking alternatives that can lead to undesirable consequences.