【简答题】从某高校2000名患近视的同学中,按重复抽样方法随机抽取46名学生用某中医疗不矫正其近视,其中30名有效,要求计算: (1)近视治疗总体有效率的点估计为___%,治疗有效率的抽样平均误差为___%。 (2)以95%的置信度估计近视治疗总体有效率的估计区间为___%到___%。 (3)以95%的置信度估计近视治疗有效的学生人数的估计区间为___人到___人。 注:(1)、(2)计算结果均保留两位小数...
【单选题】对于电热式燃油表,当油量增多时,浮子位置高,电流(),指针偏右
【单选题】One day Jack's wife was cleaning the house. 'Look at all these umbrellas (雨伞) ,' Jack's wife said to him. 'There are eight and they are broken.' 'I'll take them all to the umbrella shop. Maybe the wor...
A.
She was doing some washing.
B.
She was doing some cleaning.
C.
She was doing some shopping.
【判断题】%.黄帽子是乐观帽,每个人都只说乐观的想法。
【简答题】从某高校2000名患近视的同学中,按重复抽样方法随机抽取46名学生用某中医疗不矫正其近视,其中30名有效,要求计算:
(1)近视治疗总体有效率的点估计为___%,治疗有效率的抽样平均误差为___%。
(2)以95%的置信度估计近视治疗总体有效率的估计区间为___%到___%。
(3)以95%的置信度估计近视治疗有效的学生人数的估计区间为___人到___人。
注:(1)、(2)计算结果均保留两位小...
【多选题】从食品添加剂的来源看属于天然的食品添加剂有
【单选题】Tom was playing football on the road. A car was coming, Jack called to Tom, 'Look out!'. Here 'look out' means ______. [ ]
【多选题】如果出现主观原因造成的漏接,导游人员的处理方法包括( )
E.
采取必要弥补措施,高质量完成接待计划内的活动内容