NIFT PG 2019 Question Paper with solutions

Question : 21 of 150

Marks: +1, -0

The mean value of 20 observations was found to be

75,

but later on it was detected that 97 was misread as

79 .

Find the correct mean.

Solution:

Given, mean value of 20 observations

=75

Sum of all 20 observations

=75 × 20=1500

Now, according to the question,
New mean

=\;{1500-79+97}/{20}=\;{1500+18}/{20}

=\;{1518}/{20}=75.9

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