医学实验中除了处理因素以外,还存在着许多可能影响实验结果的因素,如观测者的感官误差,仪器的测量误差,实验过程的条件误差,人或动物的个体差异等。实验设计的一项基本任务就是尽量避免或控制这些因素对实验结果的影响。例如,两名医生(A_1,A_2)分别用两个血压计(B_1,B_2)测量两名健康男青年(C_1,C_2)的血压,实验结果(舒张压)如表1所示。 In addition to the processing factors in medical experiments, there are many factors that may affect the experimental results, such as the sensory error of the observer, the measurement error of the instrument, the condition error of the experimental process, and the individual differences of the human or animal. One of the basic tasks of experimental design is to try to avoid or control the influence of these factors on the experimental results. For example, two doctors (A_1, A_2) used two sphygmomanometers (B_1, B_2) to measure the blood pressure of two healthy young men (C_1, C_2). The experimental results (diastolic blood pressure) are shown in Table 1.