[填空题]
A student measures a length five times. All of the measurements xyxc gd r,.9k14f*y. lqlv2kr lie betksih83fv // jv3ony;tween $18.8 \mathrm{~cm}$ and $19.2 \mathrm{~cm}$. What should the student quote as the absolute uncertainty in the length? The absolute uncertainty is $cm$ (Do not include the $\pm$ symbol nor the unit)