[填空题]
A student measures a length j( vncquq6qt,zt4ti gd+5d 8 -five times. All o60u :mi3xiq-: tbywzsf 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.)