Yes the number of ...

Yes the number of latrines/toilets necessary is definitely different if one is taking into consideration households and community or group toilets. In regards to households, depending on the culture, one needs to sometimes have separate toilets/latrines for the women/girls and separate ones for the men/boys. Then in order to assure young children use the toilets/latlrines, the sanitation programme should have a latrine adapted to children's use which is located very close to the house or kitchen so the child/children do not have to walk far, particularly at night. So the number depends on the number of households and the composition of the households.

With regards to group or community latrines/toilets separate ones should be constructed for the females and the males. I would have to do some more research and look at my notes from various sanitation projects I have worked on in the past to be able to give advice regarding the ratio of population to number of community toilets necessary.

But do not forget to plan hand washing facilities in proximity to the community or group toilets for if you do, you have almost defeated the health improvement aspect possible.