Incorrect statement among the following is

To get a better quality cement tricalcium silicate composition should be more

For a good quality of cement CaO to other oxides ratio is 2.5 to 4

Plaster of paris is  $2{\mathrm{CaSO}}_4\cdot {\mathrm{H}}_2\mathrm{O}$

2 to 3 % gypsum is added to cement to slow down the process of setting of cement