Say a business found that 29.5% of customers in Washington prefer grey suits. The company chooses 8 customers in Washington and asks them if they prefer grey suits. What assumption must be made for this study to follow the probabilities of a binomial experiment?

The assumption that must be made for this study to follow the probabilities of a binomial experiment is that there must be only two outcomes of each trail in this study (meaning that it is either they prefer grey suits or they do not prefer grey suits). There must be no other option apart from those two options and each of the independent trails must be mutually exclusive, meaning that the two required options cannot occur together. It is either the first option (prefer grey suits) or the second option (do not prefer grey suits).