GRE
The standard deviation of the seven numbers $$-c, -b, -a, 0, a, b, c$$
The standard deviation of the seven numbers $$-c^{2}, -b^{2}, -a^{2}, 0, a^{2}, b^{2}, c^{2}$$
The standard deviation of data set Ⅰ
The standard deviation of data set Ⅱ
$$C_k$$
$$\frac{2k^2-1}{k+k}$$
3 times the number of elements in V
The number of elements in the set R∪S∪T
x
y
p
q+r+s
The amount of time that it takes machines K, L, and M, working simultaneously at their respective constant rates, to produce 100 units of product Z
1 hour
n
16
The perimeter of quadrilateral ABCD
8r
$$x$$
$$90$$
$$d$$
$$k^2$$
The probability that w will precede x in the sequence
$$\frac{1}{2}$$
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211本备考书籍