【简答题】John: Mary isn't going to New York next week. Rose: ______
【简答题】What isn’t Mary happy about? She isn’t happy about ____ going off _____.
【单选题】听力原文:M: Mary, why isn't Jane teaching here this term? W: She can't. She was fired. What reason is given for Jane's not teaching?
A.
She is tired of teaching.
B.
She was dismissed from her job.
D.
The school is too hot.
【简答题】把多轴电力拖动系统折算为等效单轴系统时负载转矩按什么原则折算?各轴的飞轮力矩按什么原则折算?
【单选题】从均值为μ,方差为(有限)的任意一个总体中抽取样本量为n的样本,当样本n充分大时,根据中心极限定理,样本均值 的抽样分布服从
D.
均值为 μ ,方差为 σ ^2/n的正态分布
【单选题】Mary isn't active, she is ____________. [ ]
【单选题】从均值为μ、方差为σ2(有限)的任意一个总体中抽取大小为n的样本,则
A.
当n充分大时,样本均值 的分布近似服从正态分布