Question

The mean of marks of 10 students is 20 .It was observed that the data was noted wrong as each data was decreased by 5. The students argued that the correct mean has to be 25. Are the students correct.

Answer 1

Step-by-step explanation:

ANSWER

Number of observations= 75

Mean=27

Sum of observations=75×27

Wrong value=43, Correct value=53

∴Correct sum=75×27−43+53

=75×27+10

Correct mean=

75

75×27+10

=27+

75

10

=27.133