Mathematics · Statistics

JEE Main 2025 — 23 January, Evening Shift — Question 24

The variance of the numbers $8,21,34,47, \ldots, 320$ , is $\_\_\_\_\_$

Answer: 8788

Numerical answer — enter this value.

$8+(n-1) 13=320$

$13 n=325$

$\mathrm{n}=25$

no. of terms $=25$

mean $=\frac{\Sigma \mathrm{x}_{\mathrm{i}}}{\mathrm{n}}=\frac{8+21+\ldots+320}{25}=\frac{\frac{25}{2}(8+320)}{25}$

variance $\sigma^{2}=\frac{\sum \mathrm{x}_{\mathrm{i}}^{2}}{\mathrm{n}}-(\text { mean })^{2}$

$=\frac{8^{2}+21^{2}+\ldots .+320^{2}}{13}-(164)^{2}$

$=8788$

Answer key and solution verified before publishing.

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