About State vs Sample

A state is a possible value the random variable can take — it exists whether or not you’ve observed it.

A sample is a realized observation from a distribution — a concrete outcome you observe.

Example

In a Markov chain modeling whether it rains or not:

  • State space:
  • Sample: “Today it rained” (a realized observation)

The state space exists theoretically as all possible outcomes. A sample is what you actually observe in reality.