Indicate if the following items are an event that will cause a movement along the demand curve for hot dogs of shift of the demand curve for hot dogs, holding all else constant

a) A decrease in the price of salted pretzels (a substitute for hot dogs).

This event will cause a shift in the demand curve for hot dogs because it is a nonprice factor. Since the price of salted pretzels is declining, the change in the demand curve for hot dogs will be a leftward shift.

b) A decrease in the price of hot dogs.

This event will cause a movement along the demand curve for hot dogs since it involves a change in the price, that is, it is a price factor. Moreover, this event will cause the quantity demanded of hot dogs to surge.

c) A decrease in income of consumers.

This event will cause a shift in the demand curve for hot dogs because it is a nonprice factor. Since the income of households is declining, there will be a leftward shift in the demand curve for hot dogs.