Sampling is where you take a portion of a larger group and use it to provide information about the group. It works for some purposes because of the law of large numbers and law of proportionality and law of ratios, all statistical laws.

For example. Suppose you have a drawer filled with socks. You don't know how many socks are white or black but they are all either white or black. You know there are 100 socks in the drawer. Suppose you want to find out using sampling about how many white socks and how many black socks there are.

So you grab 10 socks. 4 of the socks are white and 6 of the socks are black. So if the ratio of all socks in the drawer is the same you can conclude that 40 of the socks are going to be white and 60 are going to be black.

Things can affect sampling too. You might have automatically though that all of these socks would be paired as most people keep two socks together, and generally they pair like colors.

Suppose that the ratio was exactly 40 white socks to 60 black socks and suppose that all socks were not paired you might pull out 3 white socks and 7 black socks. You might get 5 white socks and 5 black socks. It all depends on your sample and the number of samples you make.

Sampling is most effective when you have extremely large numbers such as millions or billions or thousands of possible outcomes, but you only have the resources to count a certain number. Using statistical laws of probability and proportions you can determine with a fair bit of accuracy how many of something there is in something larger using sampling.

For example. Suppose you have a drawer filled with socks. You don't know how many socks are white or black but they are all either white or black. You know there are 100 socks in the drawer. Suppose you want to find out using sampling about how many white socks and how many black socks there are.

So you grab 10 socks. 4 of the socks are white and 6 of the socks are black. So if the ratio of all socks in the drawer is the same you can conclude that 40 of the socks are going to be white and 60 are going to be black.

Things can affect sampling too. You might have automatically though that all of these socks would be paired as most people keep two socks together, and generally they pair like colors.

Suppose that the ratio was exactly 40 white socks to 60 black socks and suppose that all socks were not paired you might pull out 3 white socks and 7 black socks. You might get 5 white socks and 5 black socks. It all depends on your sample and the number of samples you make.

Sampling is most effective when you have extremely large numbers such as millions or billions or thousands of possible outcomes, but you only have the resources to count a certain number. Using statistical laws of probability and proportions you can determine with a fair bit of accuracy how many of something there is in something larger using sampling.