Question

Arithmetic mean of nine observation is calculated as 38 . But in doing so,an observation 27 is mistaken for 72. Find the actual mean of data

Answer 1

Answer:

33

Step-by-step explanation:

mean of nine observation = 38

Mean = Sum of observation / Number of Observation

38 = Sum of Observations/ 9

=> Sum of observations = 38 * 9

=> Sum of observations = 342

But 27 is mistaken for 72

So to correct it 72 will be Subtracted from Sum & 27 will be added

So correct Sum = 342 - 72 + 27 = 297

Mean = 297/9

Mean = 33

Another way to solve with calculating total Sum

27 is mistaken for 72

27 - 72 = -45 is correction factor

Mean of correction factor = -45/9 = -5

Correct Mean = Mean + Correction

= 38 + (-5)

= 38 -5

= 33

Answer 2

Answer:

hey!!

Step-by-step explanation:

mean=sum of observations/ total observations

38=sum/9

38×9=sum

342=sum

If a number is mistakenly written as 72 then 27 should be added to the sum

sum=342

actual sum should be :

342-45

=387

mean=sum/total observations

=297/9

= 33