Mass. Gen. Laws ch. 94, § 287

An average of not less than ten units of thread of the same type and put-up, selected at random from such units referred to in section two hundred and eighty-five, kept for the purpose of sale, offered or exposed for sale, or sold, shall not weigh or measure more than three per centum less than the net weight or number of yards marked on such units or on the package containing such units.