Question

question 9 (4 points)
a researcher is studying whether being a smoker causes people to get colds more often. classify each method as a survey, an experiment, or an observational study. then explain which method would be the most reliable.
method a: choose people who already smoke and who do not and monitor how many colds they get in a period of years.
method b: choose 100 people at random. have 50 people smoke regularly for six months and 50 people not smoke for six months. then monitor how many of the 100 people get colds within the next six months.
method c: ask people who currently have a cold whether or not they smoke.
tell whether each method of gathering data is a survey, an observational study, or an experiment. which option would give the most reliable results?

Explanation:

• Method A: Observational study (observes existing groups without intervention).
• Method B: Experiment (assigns smoking/nonsmoking, manipulates variable).
• Method C: Survey (asks people about smoking status).

Experiments (Method B) are most reliable for causation as they control variables and assign groups, reducing confounding factors. Observational studies and surveys have more confounding variables (e.g., lifestyle differences in Method A, recall bias in Method C).

Answer:

• Method A: Observational Study
• Method B: Experiment
• Method C: Survey
• Most reliable: Method B (Experiment)