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Download 4-6 Designing Experiments (Block, Random, Matched Pairs)
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SWBAT: Describe and implement a well-designed experimental study Lesson 4-6A Do Now: High cholesterol level in people can be reduced by exercise or by drug treatment. A pharmaceutical company has developed a new cholesterol-reducing drug. Researchers would like to compare its effects to the effects of the cholesterol-reducing drug that is currently available on the market. Volunteers who have a history of high cholesterol and who are currently not on medication will be recruited to participate in a study. (a) Design a completely randomized experiment for the study. (b) Describe an experimental design that would improve the design in (a) by incorporating blocking. (c) C an the experimental design in (b) be carried out in a double blind manner? Explain. SWBAT: Describe and implement a well-designed experimental study Lesson 4-6A EXPERIMENTAL DESIGNS Design an experimental outline for each of the following: 1. A food company wants to assess the nutritional quality of a new “instant breakfast” product by feeding it to newly weaned male rats and measuring their weight gain over a 28-day period. Researchers use 30 rats for the experiment where half are given the standard diet and the other are given the new diet. Outline the randomized comparative design. 2. A new weight-loss supplement is to be tested at three difference levels (once, twice and three times a day). Design an experiment, including a control group and blocking for gender, for 80 overweight volunteers, half of who are men. a) Explain carefully how you will use randomization. SWBAT: Describe and implement a well-designed experimental study Lesson 4-6A 3. A swim coach decided to design an experiment to see if Ultra Swim shampoo is better at removing chlorine that Herbal Essence shampoo from hair. The coach found 90 subjhecfts whom swim daily to participate in the experiment. The coach will measure the amount of chlorine before the swimmer showers, as well as after the swimmer showers for a week and record the results. Outline the experiment and include a control group. a) What are some possible confounding variables? 5. A researcher wants to determine the effect of different grades of gasoline on the gas mileage of cars. The two grades of gasoline being tested are regular and premium, and the cars used in the test will be 10 sedans and 10 compacts. a) Outline a completely randomized design to determine if the grade of gasoline used affects the gas mileage. C learly explain how the cars would be randomly assigned to the treatments. b) The researcher believes the type of car will also affect the gas mileage. Outline an appropriate block design for the experiment using the type of car as the blocking variable. Explain how the cars would be randomly assigned to the treatments. c) Describe in detail the design of a matched pairs experiment in which each car serves as its own control.
