几道郁闷题

yg007

survery of 800 students to two things’s attitude---- M and R
the response can be YES, NO, Not sure
the table in the question tells us that:
to M: 500 Yes;200 No; 100 not sure
to R: 400 Yes;300 No; 100 not sure
200 only reply Yes to M ;
ask what is the number of student who don't reply YES to either  M or R
此题无头绪

一个数列的mean是m, 标准方差是d;另外一个数列包含了上述数列所有数加多一个x,标准方差是s, 问是否s>d? (1) x=m (2) 忘了
此题我认为通过已知条件就能推出s=d，对否？

Sequence A: X1, X2, X3, …….X10
Sequence B: Y1, Y2, Y3,……...Y10
If the numbers in B are the remainders of the results of numbers in A are divided by two. Then the sum of B is ?
A: Sequence A consists of six even numbers
B: The sum of sequence A
我选e,可答案是a

smart

一个数列的mean是m, 标准方差是d;另外一个数列包含了上述数列所有数加多一个x,标准方差是s, 问是否s>d? (1) x=m (2) 忘了
此题我认为通过已知条件就能推出s=d，对否？

同意通过已知条件就能推出s=d

smart

因为(1) x=m 两个数列的标准方差是一样的。