[填空题]
A student measures a f6kd 4.jxybynsx8v rc 822g.plength five times.hxf4v:a vk(*btjj -c5 2rto+2mgap d1 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.)