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Question: Answered & Verified by Expert
The mean of 10 observations is 5 . If 2 is added to each observation and then multiplied by 3 , then what will be the new mean
MathematicsStatisticsNDANDA 2012 (Phase 2)
Options:
  • A 5
  • B 7
  • C $15 \quad$
  • D 21
Solution:
2324 Upvotes Verified Answer
The correct answer is: 21
Given : Mean of 10 observations is 5 .
Mean of 10 observations is 5
$\Rightarrow \frac{\sum_{i=1}^{10} x_{i}}{10}=5$
According to the Question
$\frac{\sum_{i=1}^{10} 3\left(x_{i}+2\right)}{10}=$ New mean
$\Rightarrow \frac{3 \sum_{i=1}^{10} x_{i}}{10}+\frac{3 \times 2 \times 10}{10}=$ New mean
$\Rightarrow 3 \times 5+6=$ New mean $\quad \Rightarrow 21=$ Newmean

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