[填空题]
A student measures a length five times. All of the measurementr w3v,bklzn a 2ilo 7gi163r7js x * e(-d dwnh,ye)xiib94nv7f 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.)