疑似第四题原题,不确定
Group X has 6 students, 3 boys who are each j years old, and 3 girls who are each k years old. Group Y has 4 students, 1 boy who is j years old and 3 girls who are each k years old. What is the variance of the ages in group Y?
(1) The standard deviation of X is 0
(2) j=k
上面第三题原题
There are 5 consecutive integers. If the product of the 5 numbers is not zero, what is the number of the negative numbers of them?
1) The greatest number of the 5 numbers is less than 5.
2) At least one of the 5 numbers is negative.
答案是D