COMPONENTS OF AN EXPERIMENT? Interested in finding a way to relieve cancer-relat

Question

COMPONENTS OF AN EXPERIMENT? Interested in finding a way to relieve cancer-related fatigue, Mayo Clinic randomly divided 282 cancer patients into one of four treatment groups-those taking 740, 1000, or 2000 mg of ginseng daily or a placebo. After two months, participants taking the highest dosages of ginseng had more energy and were more active than those getting the lowest dose or placebo, who felt little improvement. In this experiment, The population of interest is The subjects of this experiment are The response variable is The factor is List the treatments: EXPERIMENTAL DESIGN? A researcher wants to investigate a new shampoo that is designed to boost hair volume. Such shampoos work by slightly increasing the diameter of hair shafts. Does this shampoo work? For each of her volunteer subjects, she will collect one hair selected at random before using the shampoo, and a second randomly chosen hair removed after using the shampoo. To eliminate bias, an assistant who does not know which hair was removed first will measure the diameters of each. The researcher is looking for a statistically significant increase in diameter after shampooing. What experimental design is this? A. Matched pairs B. Completely randomized C. Case-control study D. Cross-sectional . In this experiment, act of shampooing involves wetting the hair and then drying it. Therefore we cannot say for sure that any observed increase in diameter was not caused by the hair absorbing some water. What do we call this experimental flaw? A. the placebo effect B. Irreproducibility C. Double blind D. Confounding THINK ABOUT: How might the design be changed to eliminate this flaw? The "statistically significant increase" mentioned above refers to A. The increase in diameter is visible to the naked eye B. Every subject's hair diameter increased after shampooing C. The average increase was so large it is unlikely to be due to random chance D. A majority of observers would agree that the increase in diameter is significant

Explanation / Answer

The population of interest is: 282 Cancer patients

The subjects of this experiment are: Finding a way to relieve cancer- related fatigue

The response variable is: activeness or improvement in patients

List the treatments: 740 mg of ginseng, 1000 mg of ginseng, 2000 mg of ginseng, placebo

# What experimental design is this?

Answer: A. Matched pairs

# What do we call this experiment flaw?

Answer: D. Confounding

# The "statistically significant increase" mentioned above refers to

Answer: B Every subject's hair diameter increased after shampooing

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