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Q.
The random error in the arithmetic mean of $100$ observations is $x$ ; then the random error in the arithmetic mean of $400$ observations would be
NTA AbhyasNTA Abhyas 2022
Solution:
Random error is inversely proportional to the number of observations
$\therefore $ $Error \propto \frac{1}{o b s e r v a t i o n}$
$\frac{E_{1}}{E_{2}}=\frac{O_{2}}{O_{1}}$
$E_{2}=\frac{x}{\frac{400}{100}}$
$E_{2}=\frac{x}{4}$