Answer
a. The study is inaccurate.
b. Parameter
c.Observational Study
Work Step by Step
a. The study is inaccurate because they are basing the data on an incomplete study giving that only 7000 people responded out of 25,000 questionnaires that were sent out. Therefore it is not representative of the population and inaccurate.
b. It is a parameter because it is describing an entire population.
c. It is observational because all variables are not controlled like in an experimental study.