皮皮学，免费搜题
登录
搜题
【单选题】
从均值为200,标准差为 50 的总体中抽取容量为 100 的简单随机样本,用样本均值估计总体均值。样本均值的数学期望是 ( ) 。A.
100
B.
150
C.
200
D.
250
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】When I wanted to express my thanks to him，words _____ me. I just held his hands firmly and choked.
A.
left
B.
fled
C.
forgot
D.
escaped
【单选题】听力原文：M: The driver must have been driving too fast. W: I don't think so. He crashed into the tree because he was trying to avoid a bicycle in front of him, Q: What happed to the driver? (18)
A.
He was driving too fast2
B.
He ran into a bicycle.
C.
He hurt his back and his head.
D.
He ran into a tree.
【单选题】下列不属于预算定额中材料消耗量计算方法的是( )。
A.
凡有标准规格的材料,按规范要求计算定额计量单位的耗用量
B.
凡设计图纸标注尺寸及下料要求的按设计图纸尺寸计算材料净用量
C.
换算法
D.
以劳动定额为基础确定
【简答题】a firmly held opinion, often a religious belief
【单选题】★定额材料消耗量的组成中,下列不属于定额规定的材料消耗量的是( )。
A.
场内运输不避免的损耗
B.
内堆放不可避免的损耗
C.
加工制作的合理损耗
D.
场外运输不可避免的损耗
【单选题】When I wanted to express my thanks to him，words ___ me. I just held his hands firmly and choked.
A.
left
B.
fled
C.
forgot
D.
failed
【单选题】定额材料消耗量的组成中，下列不属于定额规定的材料消耗量的是( )。
A.
场内运输不避免的损耗
B.
场内堆放不可避免的损耗
C.
加工制作的合理损耗
D.
场外运输不可避免的损耗
【单选题】Starting air valves are held firmly on their seats by_______.
A.
cam rollers on the camshaft
B.
spring force
C.
air pressure on top of the valve differential piston
D.
air pressure on the bottom of the valve differential piston
相关题目：