The sample of telephone exchanges called was randomly selected by a computer from a complete list of more than 42,000 residential exchanges across the country.

The sample of telephone exchanges called was randomly selected by a computer from a complete list of 2,500 residential exchanges across the state.

Both the new sample and the earlier sample of telephone exchanges were randomly selected by computer from a complete list of more than 42,000 active residential exchanges across the country.

The sample of telephone exchanges called was randomly selected by a computer from a complete list of active residential exchanges in the country.

The sample of telephone exchanges called was randomly selected by a computer from a complete list of active residential exchanges across New York City.

The samples of telephone exchanges called were randomly selected by a computer from complete lists of active residential exchanges across the country and throughout New York City.

The list of more than 36,000 residential exchanges is maintained by the Marketing Systems Group of Philadelphia.

The telephone exchanges called were randomly selected by a computer from a complete list of more than 42,000 active residential exchanges in the United States.