Name: _______________________
Math 80 - Quiz #6 (Chapter 12)
1. Administrators at a hospital are concerned about the possibility of drug abuse by people who work there.
They decide to check on the extent of the problem by having a random sample of the employees undergo
a drug test. Several plans for choosing the sample are proposed. Name the sampling strategy that is
trying to be implemented:
a. There are four employee classifications: doctors, medical staff (nurses, technicians, etc.), office
staff and support staff (custodians, maintenance, etc.). Randomly select ten people from each
category.
STRATIFIED
b. Each employee has a 4-digit ID number. Randomly choose 40 numbers.
SIMPLE RANDOM SAMPLE
c. At the start of each shift, choose every tenth person who arrives for work.
SYSTEMATIC
d. Randomly select a department (say, radiology) and test all the people who work in that
department – doctors, nurses, technicians, clerks, custodians, etc.
CLUSTER
2. Name and describe the kind of bias that might be present if the administration decides that instead of
subjecting people to random testing they’ll just…
a. Interview employees about possible drug abuse.
Type of bias:
RESPONSE BIAS
Why might this give biased results?
PEOPLE MIGHT FEEL THREATENED SO THEY MIGHT NOT ANSWER TRUTHFULLY.
THIS WOULD LIKELY RESULT IN UNDERSTIMATING THE TRUE PROPORTION OF
DRUG USERS. DRUG USERS WILL LIKELY NOT ADMIT THEY ARE USING.
b. Ask people to volunteer to be tested.
Type of bias:
VOLUNTARY RESPONSE BIAS
Why might this give biased results?
LIKELY, ONLY THOSE WHO ARE NOT DRUG USERS WILL VOLUNTEER. LIKELY
THE PROPORTION OF DRUG USERS WILL BE UNDERESTIMATED.