## Populations, Samples and Processes

A **census** means you poll every member of the population.

**Univariate** vs **bivariate** or **multivariate**: Univariate means
there’s only one variable under consideration.

**Descriptive** statistics merely describes the data, without drawing
conclusions. Think computing the mean, standard deviation, plotting the
data, etc.

**Inferential** statistics involves generalizing from the sample to the population.

Probability and statistics are the inverses of each other. In probability, the distribution of the population and its properties are known, and we calculate things. In statistics, we are estimating the distribution and trying to know the population.

**Enumerative** vs **analytical** studies:

- Enumerative is the “usual” case where a population exists and we are sampling from it. It is well understood and the conclusions are reliable.
- Analytical studies don’t have an actual population. As an example, you use samples for an existing industrial process and make conclusions about the next generation process. Never do this without a domain expert!