Photo of teacher and child.
Illinois State Museum Changes:
Because of high numbers involved, only randomly selected visitors and students will be interviewed after their visit to the Changes exhibit at the Illinois State Museum. For example, the interviewers might talk only to every fifth person who crosses a line at the exhibit. Click Cases and select Illinois State Museum Changes to review the case.

Photos of couple
West Dakota Library Rx
All WD residents are part of the target audience, but they cannot all be surveyed. A random sample of residents is assumed to be representatives of the whole group.

Some or all of the participants?

Photo of girl writing
Springfield Library Summer Reading Program
All the participants are students in an urban library district. Should reading tests be monitored for all participants? At-risk students only? Those who complete a specific number of activities?

People other than the participants?

Photo of child reading
Springfield Library Summer Reading Program
Are parents likely to be better sources of information about their children (such as number of hours spent reading and attitude toward reading) than the children themselves?

This file contains all the long descriptions for the page "Choosing data sources and the people they’re applied to." When you have finished reading this, you can proceed to the text that begins "Remember: Collecting data" at the bottom of the page.