Statistics And Probability Question 383
Question: In a series of $ 2n $ observations, half of them equals $ ‘a’ $ and remaining equals ‘__a’. If S.D. is 2, then $ | a | $ equals
Options:
A) $ \frac{1}{n} $
B) $ \sqrt{2} $
C) $ 2 $
D) $ \frac{\sqrt{2}}{n} $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ \because \sigma =\sqrt{\frac{\Sigma xi^{2}}{N}-{{( \frac{\Sigma x_{i}}{N} )}^{2}}} $
$ \therefore 2=\sqrt{\frac{(a^{2}+a^{2}…‘2n’times)}{2n}-0} $
$ \Rightarrow 4=\frac{2na^{2}}{2n}\Rightarrow a^{2}=4\Rightarrow | a |=2 $
BETA
