Q5 of 14 Page 269

Mean of 50 observations was found to be 80.4 but later on it was discovered that 96 was misread as 69 at one place. Find correct mean.

Mean of 50 observations = 80.4



where x is sum remaining 49 observations


x + 69 = 4020


x = 3951 ..(i)


Adding 96 to the sum of remaining terms


= 3951+96


= 4047


Now finding means for 50 terms



So, the corrected mean is 80.94


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