Question

A study published in a medical journal suggests that it is dangerous to enter a hospital on a weekend. During a12​-year

​period, researchers tracked over 88 million emergency admissions to hospitals in a certain city. Their findings revealed that patients admitted on weekends had a much higher risk of death than those who went to the emergency room on weekdays.

​a) The researchers said the difference in death rates was​ "statistically significant." Explain in this context what that means.

A.

The difference between death rate on the weekend and death rate during the week is less than would be expected due to natural sampling variation.

B.

The difference between death rate on the weekend and death rate during the week is greater than would be expected due to natural sampling variation.

C.

The difference between death rate on the weekend and death rate during the week is greater than would be expected due to a causal effect.

D.

The difference between death rate on the weekend and death rate during the week is obvious.

​b) What kind of study was​ this? Explain.

A.

This is an experiment. The researchers randomly selected people injured during weekends and week days and compared the survival rates of the two groups.

B.

This was a prospective observational study. The researchers identified hospitals in a city and tracked admissions to the emergency rooms.

C.

This is a retrospective observational study. The researchers tracked people injured during weekends and week days and compared the survival rates of the two groups.

D.

This is an experiment. The researchers identified hospitals in a city and tracked admissions to the emergency rooms.

​c) If you think​ you're quite ill on a​ Saturday, should you wait until Monday to seek medical​ help? Explain.

A.

​Yes, clearly there is some reason why emergency rooms are unable to keep their patients alive during the weekend.

B.

It depends on whether or not the probability of dying of the illness is greater than the probability of dying in the hospital when admitted during the weekend.

C.

​No, this study cannot prove anything about causation. In​ contrast, it is certain that a serious illness will kill me if I do not seek medical attention.

​d) Suggest some possible explanations for this troubling finding.

A.

Dangerous workplace accidents are more likely to occur on weekends and may explain the higher death rate.

B.

Perhaps bridge collapses have a significant impact on the weekend death rate due to higher travel volume.

C.

Medical personnel are less likely to work on​ weekends, meaning that people who are admitted into the hospital are less likely to receive sufficient care.

D.

Alcohol​ use, which may lead to traffic accidents and​ violence, might have something to do with the higher death rate on the weekends.

Answer 1

a) B. The difference between death rate on the weekend and death rate during the week is greater than would be expected due to natural sampling variation.

b) B. This was a prospective observational study. The researchers identified hospitals in a city and tracked admissions to the emergency rooms.

c) C. ​No, this study cannot prove anything about causation. In​contrast, it is certain that a serious illness will kill me if I do not seek medical attention.

d) C. Medical personnel are less likely to work on​ weekends, meaning that people who are admitted into the hospital are less likely to receive sufficient care.