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Home  >>  JEEMAIN and NEET  >>  Mathematics  >>  Class11  >>  Statistics

The standard deviation of -1, -2, -3, -4, -5, -6, -7 is

$\begin {array} {1 1} (A)\;2 & \quad (B)\;4 \\ (C)\;-2 & \quad (D)\;-4 \end {array}$

1 Answer

$AM = \large\frac{-(1+2+....+7)}{7}$
$ = -\large\frac{28}{7}$ $ = -4$
$ \therefore \sigma^2 = \large\frac{\Sigma x_i^2}{n}$ $ - ( \overline x)^2=4$
$ \sigma = 2$
Ans : (A)
answered Jan 28, 2014 by thanvigandhi_1
 

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