Editing Mixture distribution (section)

==Mixtures within a parametric family==
The mixture components are often not arbitrary probability distributions, but instead are members of a [[parametric family]] (such as normal distributions), with different values for a parameter or parameters. In such cases, assuming that it exists, the density can be written in the form of a sum as:
<math display="block"> f(x; a_1, \ldots , a_n) = \sum_{i=1}^n \, w_i \, p(x;a_i) </math>
for one parameter, or
<math display="block"> f(x; a_1, \ldots , a_n, b_1, \ldots , b_n) = \sum_{i=1}^n \, w_i \, p(x;a_i,b_i) </math>
for two parameters, and so forth.