Errors in filling prescriptions A large number of preventable errors (e.g., overdoses, botched operations, misdiagnoses) are being made by doctors and nurses in U.S. hospitals. A study of a major metropolitan hospital revealed that of every 100 medications prescribed or dispensed, 1 was in error, but only 1 in 500 resulted in an error that caused significant problems for the patient. It is known that the hospital prescribes and dispenses 40,000 medications per year.

a. What is the expected proportion of errors per year at this hospital? The expected proportion of significant errors per year?

b. Within what limits would you expect the proportion of significant errors per year to fall?