A small college wants to know what percentage of its current 2,500 students wants a switch to a quarter system. Every student in the college is polled with a question attached to the course registration form. What's the margin of error for the poll?
a. 5
b. 2
c. 0
d. It depends on the observed sample proportion.
Question 2
An observational study found a statistically significant relationship between regular consumption of tomato products (yes, no) and development of prostate cancer (yes, no), with lower risk for those consuming tomato products. Setting aside the feasibility of doing so, suppose the results had been based on a randomized experiment (instead of an observational study), in which men were randomly assigned to consume or abstain from tomato products. Which of the following problems associated with observational studies would no longer be a problem?
a. The statistically significant reduced risk of prostate cancer could be caused by confounding variables instead of by consumption of tomato products.
b. The people who volunteered for the study may not be a representative sample.
c. The people in the study may lie about what they actually ate.
d. The participants were not blind to what they were eating.
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