Okay, in all fairness - I'm a bit fluthered right now, but I'm not understanding this: "Altogether, Dr Decety and his colleagues recruited 1,170 families for t

Okay, in all fairness - I'm a bit fluthered right now, but I'm not understanding this: "Altogether, Dr Decety and his colleagues recruited 1,170 families for their project, and focused on one child per family. Five hundred and ten of their volunteer families described themselves as Muslim, 280 as Christian, 29 as Jewish, 18 as Buddhist and 5 as Hindu. A further 323 said they were non-religious, 3 were agnostic and 2 ticked the box marked “other”. So the sample size is 1,170 and then the article talks about five hundred and ten? What happened to the other six hundred and sixty participants?