If the random error in the arithmetic mean of 50 observations is a, then the random error in the arithmetic mean of 150 observations would be-
1)a
2)3a
3) a/3
4)2a
The answer given is a/3. How is that possible?! Please tell me the reasons/
if no. of observations increase then error decreases
Rule : no. of observations *error = constant
n1 e1 = n2 e2
150 e1 = 50 a
e1 = a/3
Rule : no. of observations *error = constant
n1 e1 = n2 e2
150 e1 = 50 a
e1 = a/3
