1. A rancher wishes to use angora goats to control leafy spurge, a noxious invading weed. He contacts the university about setting up an experiment in an area covered with leafy spurge. He wishes to use pens of angora goats on part of the spurge and an appropriate herbicide on another portion of the spurge. Not wanting to use chemicals any more than absolutely necessary, the rancher wants to see whether the goats can control the weed long-term as well or better than the herbicides. What can be used as a control group when comparing the effectiveness of the herbicide with the goats on the leafy spurge? (Hint: An area must be left in which the spurge is left untouched by either treatment.)
2. Obesity in white lab mice has been related to increased problems with infertility. To verify this, a researcher wishes to try a new high-fiber diet ration on a group of obese white mice to see if she can induce weight loss in the mice, and thus increase their fertility. What does she need to use for a control group? (Hint: She needs to compare this group of obese mice with another group of obese mice on standard ration, keeping all other variables constant.)