Question

If the random error in the arithmetic mean of 50 observations is alpha then the random error in the arithmetic
3.
mean of 150 observations would be
(1) a
(2) 3a
a
(3)
(4) 2a
3​

Answer 1

Random Error Inversely proportional to no. of observations

$\frac{e1}{e2} = \frac{n2}{n1} \\ \\ \frac{a}{e2} = \frac{150}{3} \\ e2 = \frac{a}{3}$