The National Claims History (NCH) contains records for 999,645 Medicare patients who were discharged from acute care hospitals in October 2008. The Department of Health and Human Services performed a detailed audit of adverse medical events on a random sample of 780 drawn at random without replacement by assigning a random number to each patient on the list and then choosing random integers between 1 and 999,645.
(a) What kind of sample is this (random, systematic, stratified, cluster)?
(b) Is this population effectively infinite?