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AP EAMCET · Maths · Statistics

The standard deviation and mean of five observations are 0 and 9 respectively. If one of the observations is changed such that the mean of the new set of five observations becomes 10 , then their standard deviation is

  1. A 1
  2. B 2
  3. C 3
  4. D 0
Verified Solution

Answer & Solution

Correct Answer

(B) 2

Step-by-step Solution

Detailed explanation

Let the five observations are \(x_1, x_2, x_3, x_4, x_5\). So, mean \(=\frac{x_1+x_2+x_3+x_4+x_5}{5}=9\) (given) \(\Rightarrow \quad x_1+x_2+x_3+x_4+x_5=45\) and standard deviation \(=\sum_{i=1}^5 \sqrt{\frac{\left(9-x_i\right)^2}{5}}=0\) (given)…