幾個時段請大家填寫,會比較有代表性。這類的抽樣常用在先導實驗中。 Boxill, Ian; Chambers, Claudia; Wint, Eleanor. Introduction to Social Research With Applications to the Caribbean. University
Pointon, Lyn Powell, Paul S. Siedlecki, John Baum, Richard Chubb, Robin Fieldhouse, James Muxworthy, Alex Nivlet, Rachel Stenson, and Eleanor Warwick. Process