Question

mean of 30 observation is 12 .one observation 47 was misread as 74 .find the corrected mean

Answer 1

Sum = 30*12= 360 So 360-47+74= 313+74=387 So new sum is 387 Mean = 387/12 = 32.25

Answer 2

incorrect mean = 30× 12=360. new mean = 360 - 74 + 47= 333. correct mean =333÷30=11.1