问题
单项选择题
同一组数值型变量资料所计算的均数与标准差的关系是（）
A.均数一定大于标准差
B.均数一定小于标准差
C.均数一定等于标准差
D.均数一定等于标准差的平方
E.均数的单位一定和标准差的单位相同
答案
参考答案：E
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同一组数值型变量资料所计算的均数与标准差的关系是（）
A.均数一定大于标准差
B.均数一定小于标准差
C.均数一定等于标准差
D.均数一定等于标准差的平方
E.均数的单位一定和标准差的单位相同
参考答案：E
For years scientists have been arguing about whether nature or nurture (后天) decides what people will be like. Is it nature— what people are (41) with— that decides what they will be like? (42) is it nurture —what(43) to people when they are born —that decides what they will be like? Scientists have been studying twins to (44) if they can find the answer, because twins start out with the (45) DNA. Sometimes twins don’t live together at birth and grow up in different (46) and different places— so the nature is the same for both, but the nurture is different. When scientists (47) these twins in their later life, they some times find some surprising (48). Jim Springer and Jim Lewis were adopted（收养）by two different families at birth. They first met each other again thirty-nine years (49) and discovered they had a lot in (50). Both had been (51) twice. Their first wives were both named Linda and their second wives were both named Betty! Each twin had a son — one called his son James Alan and the (52) called his son James Alan, too. Their children each had a dog called “Toy”. They even arrived at their first (53) in the same color of car. So far twin (54) seem to show that both nature and nurture are important. What we have from birth, and how and where we live help to build (55) we are.
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