什么抽样调查是按照随机原则选择若干个体的一种调查方式

问答题L C 样本 Fomm of Doc.Credit*40A:IRREVOCABLE Doc.Credit Number*20:LC-410-046405 Date of Issue31C:981022 *31D:Date 990115 Place CHINAExpiry *50:SUMITOMO CORPORATIONApplicant *59:GUANGDONG YUE FENG TRADING CO. Beneficary NO.31 ZHEN AN ROAD GUANGZHOU. Amount Pos. Neg.Tol.(%) Available with by Draft at.... Drawee CHINA *32B:Currency USD Amount 95,200.00 39A:5 5 *41D:ANY BANK BY NEGOTATION 42C:DRAFTS AT SIGHT FOR FULL INVOICE VALUE 42A:SAIBJPJT *ASAHI BANK LTD.,THE(FORMERLY THE *KYOWA SAITAMA BANK,LTD.) *TOKYO Partial Shipments Transshipment Loading in Charge For Transport to Latest Date of Ship. 43P:ALLOWED 43T:ALLOWED 44A: SHIPMENT FROM CHINESE MAIN PORT 44B: OSAKA,JAPAN44C:981231

问答题（）是按照随机原则选择若干个体的一种调查方式