4-16. Look at the figure formed by square tiles below. Think about how you could figure out how any small squares there are without counting each one.
a. Write and simplify an expression involving addition to count the number of small squares.

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