Which table shows a constant of proportionality of 2 for the ratio of string instruments to percussion instruments?
string
percussion
6
6
9
percussion
string
2
4
6
10
15
string
percussion
6
w-
string
percussion

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