a student calculated the value of mean as 20 from 25 observation. it was later discovered at the time of checking that he had copied down two values as 7 and 18 while the correct value will be 13 and 17 . find correct values of arithmetic mean
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Answer:
20.2
Explanation:
The mean is 20 from 25 observations.
So, 20*25= 500 is total data
If previously he has noted 7 and 18 which sum up to 25.
The correct value is 13 and 17 which sum up to 30.
There are 5 more in the data.
Therefore, 500+5=505
So, the new mean is ,
505/25 =20.2
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