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If the mean deviation of the numbers 1, 1+d, ..., 1+100 d from their mean is 255, then a value of d is :

  • Option 1)

    10.1

  • Option 2)

    20.2

  • Option 3)

    10

  • Option 4)

    5.05

     

 

Answers (1)

best_answer

As we learnt in 

Mean Deviation -

If x1, x2, ...xn are n observations then the mean deviation from the point A is given by :

\frac{1}{n}\sum \left | x_{i}-A \right |

-

 

mean=\frac{1+1+d+1+2d+----------1+100d}{101}=1+50d

Mean deviation

\Rightarrow \frac{1}{101}\sum_{r=0}^{100}\left | (I+rd) -(I+50d)\right |

\Rightarrow\frac{1}{101}\times 2d\times\frac{50\times51}{2}=255

d=10.1

 


Option 1)

10.1

This is correct option

Option 2)

20.2

This is incorrect option

Option 3)

10

This is incorrect option

Option 4)

5.05

 

This is incorrect option

Posted by

Plabita

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