You want to take a random sample of 30 from a population described by telephone directory with a single telephone area code. Indicate whether or not each of the following selection techniques would be a random sample and, if not, why. Using the telephone directory,

a. make 30 blind pencil stabs. b. refer to tables of random numbers to determine the page and then the position of the selected person on that page. Repeat 30 times. c. refer to tables of random numbers to find six-digit numbers that identify the page number and line on that page for each of 30 people. d. select 30 people haphazardly.