Question

(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 designed experiment prospective retrospective completely randomized double - blind (b) which one of the following best describes the explanatory (independent) and response (dependent) variables? the explanatory variable is the age group and the response variable is the percentage of dogs who contracted canine flu. the explanatory variable is the medical history and the response variable is the percentage of dogs who contracted canine flu. the explanatory variable is the age group and the response variable is the medical history. the explanatory variable is the age group and the response variable is the percentage of dogs who contracted canine flu and the response variable is the age

Explanation:

Part (a)

A designed experiment involves manipulating variables (here, giving the vaccine) to test its effect, unlike observational studies which only observe without intervention. The company administers the vaccine and monitors outcomes, so it is a designed experiment.

Explanatory variables are independent factors being tested (here, age group, as groups are split by age), and response variables are dependent outcomes measured (here, percentage of dogs with canine flu).

Answer:

Designed experiment

Part (b)