【单选题】对于随机事件 A ,若在 n 次重复独立试验中出现了 m 次,则称 m/n 为事件 A 的
【单选题】You might have avoided the collision if you had not changed the course
A.
You might have avoided the collision if you had altered the course
B.
You might have avoided the collision if you had reduced the course
C.
You changed your course and the collision happend
D.
You changed your course and the collision had been avoided
【单选题】听力原文:Had you been out of work before you came to America? (A) No, I had been stayed at home. (B) Yes, I had been jobless for 3 months. (C) Yes, I had worked in America for one year. (33)
【简答题】设A是随机试验E的某个事件. 假设在相同的条件下将试验E重复进行n次,若在这n次试验中事件A发生了k 次,则称比值( )为事件A发生的频率.
【单选题】5,7,2′,4′,6′-五羟基黄酮结构中,酸性最弱的羟基是
【单选题】下列叙述错误的是( )
A.
频率是随机的,在试验前不能确定,随着试验次数的增加,频率越来越接近概率
C.
互斥事件不一定是对立事件,但是对立事件一定是互斥事件
D.
5张奖券中有一张有奖,甲先抽,乙后抽,那么乙与甲抽到有奖奖券的可能性相同
【单选题】随机试验中,若事件A发生的概率为5/100,则说明:
C.
将100次这种试验重复多组,平均每组中,A发生大约5次
D.
做100次这种试验,肯定有95次试验A没有发生
【单选题】下列叙述错误的是( )
A.
频率是随机的,在试验前不能确定,随着试验次数的增加,频率一般会越来越接近概率
B.
若随机事件A发生的概率为P(A),则0≤P(A)≤1
C.
互斥事件不一定是对立事件,但是对立事件一定是互斥事件
D.
5张奖券中有一张有奖,甲先抽,乙后抽,那么乙与甲抽到有奖奖券的可能性相同
【单选题】Hearing that most of the members voted against her, she _______ a smile.