• Answer of this question

    Mean of 15 observation was found to be 75.But later on it was discovered that 61 was misread as 16.Find the correct mean.
    Davneet Singh's image
    Davneet Singh

    Hi Dev,

    Mean of 15 observation = Sum of 15 observations / 15

     

    Now, incorrect mean = 75

    Therefore, Incorrect mean = Incorrect sum / 15

    75 = Incorrect Sum / 15

    Incorrect Sum = 75 x 15 = 1125

     

    Given, 61 was misread as 16.

    So, we remove 16 and add 61

    So, Correct Sum = Incorrect sum - 16 + 61

                               = 1125 - 16 + 61 = 1170

     

    Thus, Correct Mean = Correct Sum / 15

                                    = 1170/15 = 78


    Written on Feb. 28, 2017, 7:18 p.m.