In parasychological scientific research, an experimental group is a set of people who take the same tests to rate their paranormal ability. This compares with a control group, who are similarly tested and form a base line to compare against the experimental group.
Readers, please enjoy this guest blog post by Sandra Kynes, author of several books, including The Herb Gardener's Essential Guide, Plant Magic, and the new Witches' Encyclopedia of Magical Plants, among many others.
Although a few old books...