Answer
The population is all the infants in Italy. The sample is the study of 33,043 infants in Italy to find a link between rhythm abnormality and sudden infant death syndrome.
Work Step by Step
The sample is the subset of the population and the population is all the possible outcomes in a particular study. Therefore, the sample would be only the 33,043 infants that were studied in Italy out of the total amount of infants in Italy. The population would be all the infants in Italy.
