أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
Yes, it is true. Selection of sampling plays an important role if there is bias while selection of sampling then you may counter to such condition. Also, incomplete data, inaccurate values, extreme values. For example in time series or regression analysis, extreme value cause deviation of existing pattern which will help to forecast future.