题目
For a small sample from a normally distributed population with unknown variance, the most appropriate test statistic for the mean is the:
选项
A.z-statistic.
B.t-statistic.
C.χ2 statistic.
答案
B
解析
： B is correct. A t-statistic isthe most appropriate for hypothesis tests of the population mean when thevariance is unknown and the sample is small but the population is normallydistributed. ： B正确。当方差未知且样本很小，但总体呈正态分布时，t统计量最适用于总体均值的假设检验。