A.在一段較短時(shí)間內(nèi),選擇有代表性的較少量對(duì)象,對(duì)幾項(xiàng)指標(biāo)進(jìn)行一次的調(diào)查
B.在一段較長(zhǎng)時(shí)間內(nèi),選擇有代表性的較少量對(duì)象,對(duì)幾項(xiàng)指標(biāo)進(jìn)行定期的調(diào)查
C.在一段長(zhǎng)時(shí)間內(nèi),選擇有代表性的較少量對(duì)象,對(duì)幾項(xiàng)指標(biāo)進(jìn)行連續(xù)多次的調(diào)查
D.在一段較短時(shí)間內(nèi),選擇有代表性的較少量對(duì)象,對(duì)幾項(xiàng)指標(biāo)進(jìn)行定期的、連續(xù)多次的調(diào)查
E.在一段較長(zhǎng)時(shí)間內(nèi),選擇有代表性的較少量對(duì)象,對(duì)幾項(xiàng)指標(biāo)進(jìn)行定期的、連續(xù)多次的調(diào)查