Transcendental meditation (TM) is reported to have beneficial effects such as lowering blood pressure. Twenty volunteers who have no experience with TM are randomly divided into two groups. A technician takes blood pressure measurements. One group is instructed in TM and told to meditate daily for a month. The other group is given no instruction
Each person is given an identification code to keep track of his/her group affiliation and blood pressure measurement. After one month the technician measures the blood
pressure again. What are the experimental units?
The blood pressure measurements after 1 month
The 20 volunteers
The two groups: TM or no TM
The change in blood pressure measurements