[填空题]
A student measures a length five times. 4d4lnf,77fvk1gh:no p: frb3qe e9lql-ufd6.b hl1pdqma): All 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.)