Observational or Experiment?
1-4 page 31 number 7: (link to answer)
The FDA randomly selects aspirin tablets to measure the amount of active ingredients.
Observational study. Nothing is being done to change the amount of active ingredients
Observational studies: Cross sectional, retrospective or prospective?
1-4 page 31 number 11: (link to answer)
5,000 households are surveyed to determine the proportion of households tuned to Saturday Night Live.
Cross sectional. The study is done in the present time.