Find the total change in the water level for the three month period in fraction or a mixed number in simplest form first month -2 2/3 second month 25/306/3 month 7/36

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