JEE Mains · Maths · STD 11 - 13. statistics
The mean of \(6\) distinct observations is \(6.5\) and their variance is \(10.25\). If \(4\) out of \(6\) observations are \(2,4,5\) and \(7 ,\) then the remaining two observations are:
- A \(10,11\)
- B \(8,13\)
- C \(1,20\)
- D \(3,18\)
Answer & Solution
Correct Answer
(A) \(10,11\)
Step-by-step Solution
Detailed explanation
Let other two numbers be \(a\), (21-a) Now, \(10.25=\frac{\left(4+16+25+49+a^{2}+(21-a)^{2}\right)}{6}\) (Using formula for variance) \(\Rightarrow 6(10.25)+6(6.5)^{2}=94+a^{2}+(21-a)^{2}\) \(\Rightarrow a 2+\left(21-a^{2}\right)=221\)…
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