1.Two-sided tolerance limit factor k -- 双侧容限系数k（参见以下链接）
Two-sided在统计学中为“双侧”

2.confidence--置信区间

3.probability content--概率
eg.This paper compares the structure,content,and learning level of statistics and probability content of elementary school in mathematics curriculum standards between Shanghai and California,gives some advice for Chinese mathematics curriculum reform.
本文从编写体例、学习内容和学习水平三方面对上海与加州数学课程标准小学“统计与概率”部分进行比较分析,提出建议供我国数学课程改革参考.

4.acc. ISO 16269-6-6:2005
这应该是一个标准的名称，保留原文即可，参见链接pdf。