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:

  • A
    $a^2 = 4b^2$
  • B
    $a = -2b$
  • C
    $a = b$
  • D
    $a = -3b$

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