Question

Simple random sampling uses a sample of size n from a population of size n to obtain data that can be used to make inferences about the characteristics of a population. suppose that, from a population of 70 bank accounts, we want to take a random sample of nine accounts in order to learn about the population. how many different random samples of nine accounts are possible?

Answer 1

This is a question of 'how many combinations of nine accounts we can make from 70 accounts'

The formula for combination is given as
`(n!)/((n-r)!r!)`

Where n is the total population = 70 accounts, and 'r' is the number of trial = 9

Substituting n = 70 and r = 9into the equation, we have


`(70!)/((70-9)!9!) =6503352856` ways of sampling 9 accounts (when the order does not matter)

Note: You can also use the
`^nC_r` button on a scientific calculator. Type in the value of n = 70, then press the
`^nC_r` button, then type in the value of r = 9, then press 'equal'