Problem: Sampling stuffed envelopes. A large retailer prepares its customers' monthly credit card bills using an automatic machine that folds the bills, stuffs them into envelopes, and seals the envelopes for mailing.
Required:
1. Are the envelopes completely sealed? Inspectors choose 40 envelopes from the 1000 stuffed each hour for visual inspection.
2. What is the population for this sample survey? What is the sample?