00:01
What type of sampling is used here? random, systematic, convenience, stratified, or cluster.
00:08
So let's go through each of these and what they mean.
00:12
Random is truly random.
00:15
You pick out a certain number of people or pieces of data from a big pot.
00:22
So you put all of them in a big pot and you pick them completely at random.
00:27
So randomly from the population.
00:32
That's clearly not what is happening here, because they're picking everybody in certain prisons.
00:41
Although they did randomly select the five prisons.
00:45
Systematic is non -random.
00:49
You put all of your people together in the population, and you pick every, say, nth person.
00:55
So you pick every fifth person that you see.
00:58
So you pick in intervals.
01:07
So that's not random, but it's better than completely.
01:11
Convenience.
01:12
Convenience is you just do whatever's easiest.
01:17
So if you're trying to survey people, maybe you just stand in a busy mall and you ask the first people you see until you have a big enough sample.
01:27
That would be convenience.
01:28
Or maybe you call random numbers and ask them to take your survey...