A father goes into the pharmacy late at night for cold medicine for a sick child. There are many liquid cold medicines, all of which have almost...

A father goes into the pharmacy late at night for cold medicine for a sick child. There are many liquid cold medicines, all of which have almost exactly the same ingredients. Yet medicine with brand names that the man recognizes from television commercials sells for more the unadvertised versions. Explain, in economic terms, this perplexing situation to the father.