Amy loaned $5 to each of 20 people. She recorded each loan by writing -$5 in her bank book. What is the total changes in the amount of money Amy had before the loans?

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