In an attempt to measure the availability of component parts for a new product line, a manufacturer mails a questionnaire to 15 of the 25 companies that supply these components. Past experience with similar surveys has shown that such companies tend to exaggerate their ability to supply desired components on time and in the quantities desired.

Of the companies surveyed, only 8 complete and return the questionnaire. Given this scenario, identify possible sources of sampling error, response error, and nonresponse error.