第二章 误差的基本性质与处理2-6测量某电路电流共5次,测得数据(单位为mA)为168.41,168.54,168.59,168.40,168.50。试求算术平均值及其标准差、或然误差和平均误差。___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).或然误差:___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).平均误差:___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).2-7在立式测长仪上测量某校对量具,重量测量5次,测得数据(单位为mm)为20.0015,20.0016,20.0018,20.0015,20.0011。若测量值服从正态分布,试以99%的置信概率确定测量结果。___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).正态分布 p=99%时,___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).测量结果:___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).2-9用某仪器测量工件尺寸,在排除系统误差的条件下,其标准差___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).,若要求测量结果的置信限为,当置信概率为99%时,试求必要的测量次数。正态分布 p=99%时,___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).___168.41+ dfrac (168.54+168.59+168.40+168.50)(5).2-9 用某仪器测量工件尺寸,已知该仪器的标准差σ=0.001mm,若要求测量的允许极限误差为±0.0015mm,而置信概率P为0.95时,应测量多少次?