**Likelihood is the probability of the data.*

There are more complicated definitions, like ...

The density function of continuous random
variables,
, that depend on model parameters,
, and written as, is the
*probability density function* of **
**, given,
or is the **likelihood** of ,
given **
**, often written as
.

(Which definition do you prefer? Me too.)

The statistical literature often uses "*likelihood*" and "*loglikelihood*"
interchangeably, which can be confusing to the statistical newcomer, but
in practice it is rather easy to distinguish the two based on context.

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