单项选择题
A.68%
B.95%
C.99.7%
D.none of the above
单项选择题 The reason that we prefer the sample standard deviation as our measure of typical variation instead of the sample variance is that（）
单项选择题 The sum of the deviations may be 0.00.To get around this problem，we use the（）of the deviations
单项选择题 deviation is the distance between a（）and the（）.（）