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JEE Main201912 Jan 2019Morning ShiftMathematicsStatisticsActual

If the sum of the deviations of 50 observations from 30 is 50 , then the mean of these observations is :

Options

  1. A30
  2. B51
  3. C50
  4. D31

Correct answer

D. 31

Step-by-step solution

Let the observations be x 1 ,   x 2 ,   . . . ,   x 50 . Given x 1 - 30 + x 2 - 30 + . . . . . + x 50 - 30 = 50 ⇒   x 1 + x 2 + . . . . . + x 50 = 50 + 30 × 50 = 1550 Now, Mean = x 1 + x 2 + . . . . + x 50 50 = 1550 50 = 31 .

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