[填空题]
A student measures a length five timfn,olf f -3meb*l v9zx7m )ov0es. Alqnih1u4wgq- +lh/d,hc r/p.a l of the measurements lie between $18.8 \mathrm{~cm}$ and $19.2 \mathrm{~cm}$. What should the student quote as the absolute uncertainty in the length? The absolute uncertainty is $cm$ (please only input numerical value without units and without the $\pm$ symbol.)