Who were the children of Israel?
A. the Sumerians
B. the Egyptians
C. the Hebrews
D. the Muslims
What was pyramids built for?
A. the dead kings
B. conserving books
C. worshiping gods
D. religious activities
What was the Code of Hammurabi about?
A. business
B. law
C. religion
D. culture
为研究某药物的抑癌作用,使一批小白鼠致癌后,将其随机分为4组,A、B、C 3个实验组和1个对照组, A、B、C 3个实验组,分别注射0.1ml、0.3ml和0.6ml 30%的注射液,对照组不用药。经一定时间以后,测定4组小白鼠的肿瘤重量(g),以分析不同剂量药物注射液的抑癌作用有无差别。该研究设计属于( )?
A. 完全随机设计
B. 随机区组设计
C. 成组设计
D. 配对设计