A dental student wants to test if fluoride is an effective additive against tooth decay. The student studies tooth decay in a population of people who live in neighborhoods supplied with fluoridated water. This student would like to ask whether access to fluoridated water prevents tooth decay. What would be an effective control group to ask this question?
A. Individuals who have fluoride added to their toothpaste but not their water.
B. Individuals with access to fluoridated water.
C. Individuals with access to water with no fluoride added.
D. Individuals with access to differing amounts of fluoride in the water.
Clarify Question
1. What is the key concept addressed by the question?
2. What type of thinking is required?
3. What key words does the question contain and what do they mean?
Gather Content
1. What do you know about experimental design?How does it relate to the question?
Consider Possibilities
1. What other information is related to the question? Which information is most useful? What are other explanations are there for these results?
Choose Answer
1.Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
Reflect on Process
1. Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
C. Individuals with access to water with no fluoride added.
Clarify Question
1. The question is about designing an experiment.
2. This question is asking you to apply you knowledge to identify an appropriate control for an experiment.
3. The hypothesis is to test the effectiveness of fluoride in the water on preventing tooth decay.
Gather Content
1. The neighborhood being tested already has fluoride in the water. If you want to see if fluoride is effective in preventing tooth decay you need a control group with no fluoride to compare it with.
Consider Possibilities
1. What other information is related to the question? Which information is most useful?
Choose Answer
1. The best control would be a group of individuals with no fluoride in their water.
Reflect on Process
1. This question asked you to apply your understanding of a hypothesis to identify the proper control group for an experiment. If you got the correct answer, great job! If you got an incorrect answer, where did you get stuck? Did you realize that fluoride is your independent variable, this is the variable the researcher can control?Did you realize that adding any fluoride to the water of the control group would make it more difficult to test your hypothesis?
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