the average marks scored by 50 students in a class were calculated to be 38. Later it was around that marks of two students were wrongly copied as 34 and 23 instead of 43 and 32. Find correct average marks.
Answers
Given,
Average of 50 students in a class = 38
Marks of two members were wrongly copied as 34 and 23 instead of 43 and 32.
Mean = Sum of all observations / Number of Observations
let the sum of all observations be x
According to the problem,
38 = x / 50
38 × 50 = x
x = 1900
Subtract the wrongly copied numbers from the total sum.
= 1900 - (34 + 23)
= 1900 - 57
= 1843
Now add the new numbers to the total sum.
= 1843 + ( 43 + 32 )
= 1843 + 75
= 1918
Thus, new sum is 1918.
New Mean = 1918/50 = 38.36
Therefore, new Mean = 38.36
Given,
Average of 50 students in a class = 38
Marks of two members were wrongly copied as 34 and 23 instead of 43 and 32.
Mean = Sum of all observations / Number of Observations
let the sum of all observations be x
According to the problem,
38 = x / 50
38 × 50 = x
x = 1900
Subtract the wrongly copied numbers from the total sum.
= 1900 - (34 + 23)
= 1900 - 57
= 1843
Now add the new numbers to the total sum.
= 1843 + ( 43 + 32 )
= 1843 + 75
= 1918
Thus, new sum is 1918.
New Mean = 1918/50 = 38.36
Therefore, new Mean = 38.36