分層分析(stratification)是在研究分析階段時,常用來控制干擾作用的
方法,請說明分層分析的意義、進行的步驟及主要的優缺點。(25 分)
Z0.975 = 1.96、Z0.95 = 1.645、Z0.99 = 2.575
t18,0.90 = 1.33、t19,0.90 = 1.33、t20,0.90 = 1.33
t18,0.95 = 1.73、t19,0.95 = 1.73、t20,0.95 = 1.72
t18,0.975 = 2.10、t19,0.975 = 2.09、t20,0.975 = 2.09
X21,0.95 = 3.84、X22,0.95 = 5.99、X23,0.95 = 7.81