题目
A population has a non-normal distribution with mean μ and variance σ^2. The sampling distribution of the sample mean computed from samples of large size from that population will have:
选项
A.the same distribution as the population distribution.
B.its mean approximately equal to the population mean.
C.its variance approximately equal to the population variance.
答案
B
解析
： B is correct. Given a population described by any probability distribution (normal or non-normal) with finite variance, the central limit theorem states that the sampling distribution of the sample mean will be approximately normal, with the mean approximately equal to the population mean, when the sample size is large. ： B正确。 用任意存在有限方差的概率分布(正态或非正态)描述的总体，中心极限定理认为，当样本容量较大时，样本均值的抽样分布近似正态，其均值近似等于总体均值。