Video: Random error, Part I

We focus on the errors we make when we use data from a sample to tell us something about a whole population. We ask: “How wrong could I be?”

(See also the Review Questions following the movie)

[Illustrated transcript (pdf)]

After you’ve watched this video, you should be able to answer these questions:

• Do the problems caused by bad measurement systems and biased selection mechanisms go away when we get huge amounts of data?
• Do the problems caused by confounding go away when we get huge amounts of data?
• Do the problems caused by random error go away when we get huge amounts of data?
• What is a sampling error?
• Do we ever know how big the actual sampling error we incurred was? What do we try to do about that?