单项选择题

If the average(arithmetic mean)of x，y，x，5 and 7 is 8，which of the following must be true（）
Ⅰ．The median of the five numbers cannot be 5．
Ⅱ．At least one of x，y，and z is greater than 9．
Ⅲ．The range of the five numbers is 2 or more

A. Ⅰ only
B. Ⅱ only
C. Ⅲ only
D. Ⅰ and Ⅲ
E. Ⅱ and Ⅲ

<上一题 目录 下一题>
热门 试题

单项选择题
If in an experiment the probabilities of obtaining the values a1，a2，a3，a4， and a5are p1，P2，P3，P4 and P5，respectively，then the expected value is defined as a1p1+a2p2+a3p3+a4p4+a5p5．For the values and their corresponding probabilities in the table above，what is the expected value（）

A. 350
B. 320
C. 300
D. 270
E. 250
单项选择题
The odds that a certain event will occur is the ratio of the probability that the event will occur to the probability that it will not occur．If the odds that Pat will win a prize are 4 to 3，what is the probability that Pat will not win the prize（）

A.a
B.b
C.c
D.d
E.e
相关试题