Explain random sampling and why it is important.

Question

Explain random sampling and why it is important.

Answer 1

          A random sample of ONE measurement from a population of N measurements is one in which each of the N measurements has an equal probability of being selected.

                A random sample of n measurements from a population is one in which every different sample of size n  from the population has an equal probability of being selected.

 

                  What is the importance of random sampling?       We must know how the sample was selected so that we can determine its probability. The probabilities of samples selected in a random manner

can be determined, thus enabling us to make valid inferences about the population from which the sample was drawn.  Nonrandom samples have unknown probabilities associated with them and hence are useless for purposes of statistical inferences.

Answer 2

Simply put, random sampling is a method in which all members of a group equally have a chance of being chosen.  There is no predetermined pattern to the selection.

This manner of selection is important becausevit increases the likelihood of a varied populous' responses/input and therefore a broader/fuller statistical model.