السوال الذي بملف سحاب سوال رقم ((22)) خطاء



الجواب d
وهنا الدليل من المحاضرة 10
But in order to constitute a proper variable a good
categorisation/classification system should: be exhaustive,
have mutually exclusive categories, not mix categories of
different types in one set, have unambiguously defined
categories, etc