the mean of the 100 item is 49. later it was discovered that 3 items which should have been 60, 70, and 80 were wrongly taken as 40, 20 and 50 respectievely. the correct mean is  [ 40, 32 , 35, 25, 45].            sir please answer it in simple way.          

Asked by Rony Joseph | 3rd Apr, 2014, 06:46: PM

Expert Answer:

Mean of 100 items is 49.
M e a n equals fraction numerator I n c o r r e c t space S u m over denominator T o t a l end fraction rightwards double arrow 49 equals fraction numerator I n c o r r e c t space S u m over denominator 100 end fraction rightwards double arrow I n c o r r e c t space S u m equals 4900
 
Now, Corrected Sum = 4900 - (40 + 20 + 50) + (60 + 70 + 80) .....(we need to subtract the wrong numbers from the incorrect sum and add the right numbers to get the correct sum)
 
Thus, Corrected Sum = 4900 - 110 + 210 = 5000
 
rightwards double arrow C o r r e c t space M e a n equals fraction numerator C o r r e c t space S u m over denominator T o t a l end fraction equals 5000 over 100 equals 50

Answered by  | 4th Apr, 2014, 09:57: AM

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