[填空题]
A student measures a length five times. Alli jt2283wx eh.w1bybg of the measurements li3 j66qx,ctc dye 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.)