Progression (Sequence and Series)Hard
Question
In a series of 2n observations, half of them equal a and remaining half equal -a. If the standard deviation of the observations is 2, then |a| equals
Options
A.
B.√2
C.2
D.
Solution
xi = a for i = 1, 2, ...,n and xi = - a for i = n, ..., 2n
S.D =
⇒ 2 = 
⇒ 2 = 
⇒ |a| = 2
S.D =
⇒ 2 = ⇒ 2 = ⇒ |a| = 2Create a free account to view solution
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