What is Sampling?
Sampling is a method used to infer insights or make generalizations when it’s unfeasible or simply impractical to analyze all the data under consideration.
With sampling smaller data subsets are culled from the data set and considered to represent the whole picture.
Sampling has been a tried-and-tested practice. It’s used in public opinion polls, surveys, consumer tests, basically the vast majority of statistical studies. And whenever sampling kicks in, it creates a certain level of uncertainty in the observations.
For example Google Analytics applies sampling in aim to strike a balance between accuracy and processing speed. You can always see if sampling is in effect, by taking a look at the top of each report. If there’s a line saying that the report is based on less than 100% of sessions, this means that the data is sampled.