The 2013–2014 Recruiting Trends report, produced each year by Michigan State University, reports that hiring over the past year of people with a bachelor’s degree increased 7%, for people with a PhD increased 26%, and for people with an MBA decreased 25%. This was based on a voluntary poll of all employers who interacted with at least one of 300 career service centers on college campuses. The survey was answered by 6,500 employers.
a. What is the population for this survey?
b. We cannot calculate the nonresponse rate. Explain what other information is needed to calculate this rate.
c. Describe two potential sources of bias with this survey.