library(MASS) data(Cars93) x <- Cars93[Cars93$Type == "Compact", "Weight"] length(x) # 样本大小 n mean(x) # 样本平均值 x̄ sd(x) # 样本标准差 s min(x) # 最小值 t.test(x, mu=2900) # 单样本t检验 shapiro.test(x) # 正态性检验