### Conditional distribution

Then we could look at the histogram of $z_2$ for a given class of $z_1$.

For instance, if we consider the 2$^\textrm{nd}$ class, $z_1\in[28.6,54.2]$ :

It shows the (empirical) conditional distribution of $z_2$ knowing that $z_1\in[28.6,54.2]$.