```{include} /../core/dataserver/attribute/introducing_tstochastic_attribute/trapezium_equation.md
```

For this distribution, the mean can be estimated through 
$\mu = \frac{1}{3(x_{\rm max} + x_{\rm up} - x_{\rm low} - x_{\rm min})} 
\bigg( \frac{x^3_{\rm max} - x^3_{\rm up}}{x_{\rm max} - x_{\rm up}} - \frac{x^3_{\rm low} - 
x^3_{\rm min}}{x_{\rm low} - x_{\rm min}} \bigg)$ 
while the variance is 
$\sigma^2 = \frac{1}{6(x_{\rm max} + x_{\rm up} - x_{\rm low} - x_{\rm min})} 
\bigg( \frac{x^4_{\rm max} - x^4_{\rm up}}{x_{\rm max} - x_{\rm up}} - \frac{x^4_{\rm low} - 
x^4_{\rm min}}{x_{\rm low} - x_{\rm min}} \bigg) - \mu^2$. 
The mode is not properly defined as all probability are equals in $[x_{\rm low}, x_{\rm up}]$ 

```{include} /../core/dataserver/attribute/introducing_tstochastic_attribute/trapezium_figure.md
```