00:01
We're given a scenario.
00:01
We want to identify the type of sampling and a possible problem that might occur here.
00:07
So the types of sampling will be simple random sampling, systematic, convenience, cluster and stratified.
00:24
These are the five types of sampling you need to be able to identify.
00:29
Simple random is you have your entire population and you pick from this population at random.
00:34
Maybe you assign everybody in the population a number and then you use a random number generator or tickets in a hat to randomly pick out as many people as you need.
00:47
Cluster and stratified, you start out with your population, you split it into subgroups based on some kind of shared characteristic, maybe age, location, that kind of thing.
00:58
In cluster sampling, you pick clusters at random until you have your sample size.
01:03
So you take entire subgroups.
01:05
Maybe you want to survey students across the entire country.
01:10
So you split them up into their schools and you randomly select entire schools to sample.
01:15
Stratified is where you split them up and then you take a sample from each subgroup, which if you imagine for the school example, you would be going to every school and probably just sampling one or two people from each.
01:28
It would take a really long time, be very expensive, but you would not miss out any of your subgroups.
01:33
So there's trade -offs.
01:36
Then we have systematic and convenience.
01:39
Systematic is done by an interval.
01:41
So you pick every nth person in the list.
01:45
You have your list, but instead of picking from it at random, you pick by intervals instead.
01:50
Convenience is the outlier, because it's not done in any kind of systematic way or random way.
01:56
It's just whatever is easiest for you...