Mixture component
= Mixture component
{title2=$P_j,\quad f_j$}
= Component distribution
{synonym}
A <mixture component> is the <conditional distribution> of $X$ given a component label $Z=j$. Its <probability density function> $f_j$ integrates to one; its weighted contribution $\pi_jf_j$ to the <mixture distribution> integrates to the <mixture weight> $\pi_j$. Thus a <mixture component> is a distribution, rather than a region assigned to it by a clustering rule.