如果变量x 的平均数和标准差是X,s,若每个变量值都加一个常数4,变成新的变量为y,那么y 的平均数和标准差是
A、X+4 和s+4
B、X+4 和s
C、X和s+4
D、X和s
E、X+4 和2+s
请帮忙给出正确答案和分析,谢谢!
优质烟叶的评吸质量表现为以下几个方面,其中不正确的是()。
A.烟气香气质好、香气量足
B.劲头大
C.杂气、刺激性小
D.燃烧性好、灰黑
此题为多项选择题。请帮忙给出正确答案和分析,谢谢!
5岁儿童有意注意时间为
A.10分钟
B.15分钟
C.20分钟
D.25分钟
E.30分钟
请帮忙给出正确答案和分析,谢谢!
关键词诊断优化高曝光高点击是指:曝光量领先于()%同行,点击量领先于50%同行的关键词
A、60
B、50
C、70
D、40
What does the word "sweat" in Paragraph One probably mean?
A.Be worried about something.
B.Feeling very hot with something.
C.Trying to avoid difficult things.
D.Getting inspiration from something.
请帮忙给出正确答案和分析,谢谢!
Why did Ms. A tell the author her family background?
A.She wanted to get donation from the author.
B.She just wanted someone to listen to her.
C.She asked the author to look after her children.
D.She intended to make clear of her illness.
请帮忙给出正确答案和分析,谢谢!
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