Does echinacea reduce the severity of the common cold? In a study designed to

evaluate the benefits of taking echinacea when you have a cold, 719 patients were randomly divided into four

groups. The groups were (1) no pills, (2) pills that had no echinacea, (3) pills that had echinacea but the subjects

did not know whether or not the pills contained echinacea, and (4) pills that had echinacea and the bottle

containing the pills stated that the contents included echinacea. The outcome was a measure of the severity of

the cold.7

(a) Identify the type of data collected in this study. Give reasons for your answer.

(b) Is this an experiment? If yes, what is the treatment?