Find the difference of 5 2/3 -4 5/9 a 3/4 b 1 1/9 c 1 1/2 d 8/9

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