Question

When an opinion poll calls landline telephone numbers at random, approximately 30% of the numbers are working residential phone numbers. the remainder are either non-residential, non-working, or computer/fax numbers. you watch the random dialing machine make 20 calls. x is the number that reach a working residential number?

Answer 1

The setup to this is to multiply the amount of calls by the expected percentage that will be residential numbers. You can then solve for X to come to the conclusion. The setup looks like so: X=(20)((30%). This gives our answer, that 6 calls should reach working residential numbers.