A group of veterinarians wants to test a new canine vaccine for Lyme disease. (Lyme disease is transmitted by the bite of an infected deer tick.) One hundred dogs are randomly selected to receive the vaccine (with their owners’ permission) from an area that has a high incidence of Lyme disease. These dogs are examined by veterinarians for symptoms of Lyme disease once a month for a period of 12 months. During this 12-month period, 10 of these 100 dogs are diagnosed with Lyme disease. During the same 12-month period, 18% of the unvaccinated dogs in the area are found to have contracted Lyme disease.
a. Does this experiment have a control group?
b. Is this a double-blind experiment?
c. Identify any potential sources of bias in this experiment.
d. Explain how this experiment could have been designed to reduce or eliminate the bias pointed out in part c.