For a frequency distribution,the standard deviation is computed by applying the formula:

  • A
    $\sigma = \sqrt{\left(\frac{\sum fd}{\sum f}\right) - \frac{\sum fd^2}{\sum f}}$
  • B
    $\sigma = \sqrt{\frac{\sum fd^2}{\sum f} - \left(\frac{\sum fd^2}{\sum f}\right)^2}$
  • C
    $\sigma = \sqrt{\left(\frac{\sum fd}{\sum f}\right)^2 - \frac{\sum fd^2}{\sum f}}$
  • D
    $\sigma = \sqrt{\frac{\sum fd^2}{\sum f} - \left(\frac{\sum fd}{\sum f}\right)^2}$

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Similar Questions

The variance of the numbers $8, 21, 34, 47, \ldots, 320$ is . . . . . . .

From the prices of shares $X$ and $Y$ below,find out which is more stable in value:
$X$ $35$ $54$ $52$ $53$ $56$ $58$ $52$ $50$ $51$ $49$
$Y$ $108$ $107$ $105$ $105$ $106$ $107$ $104$ $103$ $104$ $101$

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In a discrete data,$\frac{1}{4}$ of the observations are equal to $a$,another $\frac{1}{4}$ of the observations are equal to $-a$. Out of the remaining,half of them are equal to $b$ and the rest are equal to $-b$. If the variance of all the observations is $ab$,then:

Statement $1$: The variance of the first $n$ odd natural numbers is $\frac{n^2 - 1}{3}$.
Statement $2$: The sum of the first $n$ odd natural numbers is $n^2$ and the sum of the squares of the first $n$ odd natural numbers is $\frac{n(4n^2 - 1)}{3}$.

If each observation of a raw data whose variance is $\sigma^2$ is multiplied by $\lambda$,then the variance of the new set is

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