Air Force Primary School llorin has a population of 1530 pupils. 21 pupils were absent on a certain day. Out of the number present, 683 were girls, how many boys were present?​

Identify all the cases where non-probability sampling is used when attempting to study the characteristics of a large city. studies on every subject in the population divide a population in groups and obtain a sample studies with a limited amount of time demonstrate existing traits in a population studies with the nth person selected