In the following experiment decide whether a control group was
used and whether a placebo treatment was used.
To test an herbal treatment for depression, 100 volunteers who
suffered from mild depression were randomly divided into two
groups. Each person was given a month's supply of tea bags. For one
group, the tea contained the herb mixed with a spice tea; for the
other group, the bags contained only the spice tea. Participants
were not told which type of tea they had and were asked to drink
one cup of the tea per day for a month. At the end of the month, a
psychologist evaluated them to determine whether their mood had
improved. The psychologist did not know who had the tea with the
herbal ingredient added.
control group
placebo treatment
control group and placebo treatment
neither