[填空题]
A student measures a length five times. All of thof vx 23fj+5+pzq ulm2nicque,66e:xe measurements lie betwehrlc2w8r:z*a en $18.8 \mathrm{~cm}$ 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.)