MCQ
Variance of $^{10}C_0$ , $^{10}C_1$ , $^{10}C_2$ ,.... $^{10}C_{10}$ is 
  • A
    $\frac{{10.\,{}^{20}{C_{_{10}}} - {2^{10}}}}{{100}}$
  • B
    $\frac{{11\,{}^{20}{C_{_{10}}} - {2^{10}}}}{{11}}$
  • C
    $\frac{{10.\,{}^{20}{C_{_{10}}} - {2^{20}}}}{{100}}$
  • $\frac{{11.\,{}^{20}{C_{_{10}}} - {2^{20}}}}{{121}}$

Answer

Correct option: D.
$\frac{{11.\,{}^{20}{C_{_{10}}} - {2^{20}}}}{{121}}$
d
Variance $=\frac{\Sigma \mathrm{x}_{\mathrm{i}}^{2}}{\mathrm{n}}-\left(\frac{\Sigma \mathrm{x}_{\mathrm{i}}}{\mathrm{n}}\right)^{2}$

$=\frac{^{20} \mathrm{C}_{10}}{11}-\left(\frac{2^{10}}{11}\right)^{2}$

$=\frac{11 \cdot^{20} \mathrm{C}_{10}-2^{20}}{121}$

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