question 47 of 52\na study of treatments for ...
question 47 of 52\na study of treatments for angina (pain due to low blood supply to the heart) compared bypass surgery, angioplasty, and use of drugs. the study looked at the medical records of thousands of angina patients whose doctors had chosen one of these treatments. it found that the average survival time of patients given drugs was the highest.\nwhat do you conclude?\nwe can conclude that drugs prolong life because the study was a comparative experiment.\nwe cant conclude that drugs prolong life because the patients were volunteers.\nthis study proves that drugs prolong life and should be the treatment of choice.\nwe cant conclude that drugs prolong life because the groups might differ in ways besides the treatment.
Answer
# Brief Explanations:
This is an observational study (looking at medical - records) not a controlled experiment. There could be confounding variables like differences in patient health status, age, etc. between the groups receiving different treatments. So we can't be sure that drugs are the sole reason for the higher survival time.
# Answer:
We can't conclude that drugs prolong life because the groups might differ in ways besides the treatment.