Question
Download Solution PDFThe average weight of a group of 20 boys was calculated to be 89.4 kg and it was later discovered that one weight was misread as 78 kg instead of 87 kg. Find the correct average weight.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFCorrect average weight = Incorrect average + \(\frac{Change\: in \:weight}{No.\: of \:students}\)
Correct average weight
⇒ 89.4 + (87 - 78)/20 = 89.4 + 0.45 = 89.85 kg
∴ The correct answer is 89.85 kg
Alternate Method
⇒ Sum of observations = 89.4 × 20 = 1788
⇒ Correct sum of observations = 1788 - 78 + 87 = 1797
⇒ Correct average weight = 1797/20 = 89.85 kg
∴ The correct answer is 89.85 kg
Last updated on Mar 19, 2025
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