Use the following information to answer the following question: You wake up one morning feeling slightly under the weather. A close family member enthusiastically suggests that you take some Echinacea, an herb commonly used as a cold remedy. You then decide to design an experiment to test Echinacea and see if this claim is true. You think, "If taken at the beginning of a cold, Echinacea will reduce cold symptoms." You decide to test the effects of Echinacea on 100 people who are experiencing similar cold symptoms. Which of the following groups would represent an appropriate control in your experiment?

answer: 100 sick people given tablets similar to Echinacea but with no herb

To test if a substance will have a certain effect we always need to have a group control. That group control should have the same size as the group that's going to take the drug, in this case, one hundred people. Another important thing that makes a group control is having them not take any treatment. Lastly, the control group should be representative of the same population, the "sick population" to serve as comparison to the treatment group.