Question

a veterinary pharmaceutical company has developed a new vaccine for canine flu. to test its effectiveness, the company recruits the owners of 1000 dogs to voluntarily participate. the owners are asked about their dogs medical history and each dog is then placed into one of two groups based on its age at the beginning of the study: 5 and over, and under 5. all of the dogs are given the vaccine. the dogs are then closely monitored over a period of two years. for each group, the percentage of dogs who contracted canine flu at any point over the two years is recorded. the company will then compare these percentages between the two groups. (a) first choose whether the procedure described above is an observational study or a designed experiment. then further categorize the procedure by choosing the correct type of observational study or designed experiment. observational study prospective retrospective designed experiment double - blind completely randomized

Explanation:

The study involves assigning dogs to groups (based on age) and administering a vaccine to test its effectiveness, which is a designed experiment (intervention with the vaccine to observe outcomes).

Answer:

Designed experiment