Need to know what the mixing ratio is of cement to sand for shower pan.

If you Google "Making a mortar shower base" you will find many hits including You Tube, Sakrete and others.

Typical ratio if mixing yourself is a 1:4 (cement/sand). Use Portland cement. Mix with water to a dry pack consistency and pack to floor to attain about a 1/4" per foot pitch in floor. DON'T FORGET to put 3/4" stone around the weep holes in the drain assembly.

Mark