2.2 Study design
A student group was studying this RQ (which is not appropriate for the SCI110 Project):
Among Australians, is the median serum cholesterol concentration different for smokers and non-smokers?
The students gave the following information about their study.
Explain why each of these statements is incorrect.
- "The design is observational, as we cannot manipulate each person's serum cholesterol."
- "The Outcome is 'the median serum cholesterol levels for smokers and non-smokers'."
- "The study is not externally valid, as the results may not apply to all people in the world."
- "The response variable is serum cholesterol."
- "In this experiment, the population is 'Australians'."
- "The data file will have two columns: One for smokers, and one for non-smokers."
- "'Whether or not the person's owns a cat' is likely to be a confounding variable."
- "The observer effect is not relevant, as the participants will know they are involved in a study."