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JEE Mains · Maths · STD 11 - 13. statistics
In a series of \(2n\) observation, half of them are equal to \('a'\) and remaining half observations are equal to \(' -a'\). If the standard deviation of this observations is \(2\) then \(\left| a \right|\) equals
- A \(2\)
- B \(\sqrt 2 \)
- C \(4\)
- D \(2\sqrt 2 \)
Answer & Solution
Correct Answer
(A) \(2\)
Step-by-step Solution
Detailed explanation
Clerly mean \(A=0\) Now, standard deviation \(\sigma = \sqrt {\frac{{\sum {{{\left( {x - A} \right)}^2}} }}{{2n}}} \) \(2 = \sqrt {\frac{{{{\left( {a - 0} \right)}^2} + {{\left( {a - 0} \right)}^2} + ... + {{\left( {0 - a} \right)}^2} + ...}}{{2n}}} \)…
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