The mean of n items is ¯¯¯x. If the first term is increased by 1 second by 2 and so on, then new mean is
Options:
A . ¯¯¯x+n
B . ¯¯¯x+n2
C . ¯¯¯x+n+12
D . None of these
Answer: Option C : C Let, x1,x2.......xn be n items. Then, ¯¯¯x=1n∑xi Lety1=x1+1,y2=x2+2,y3=x3+3,.....,yn=xn+n Then the mean of the new series is 1n∑yi=1nn∑i=1(xi+i) =1nn∑i=1xi+1n(1+2+3+......+n) =¯¯¯x+1n.n(n+1)2=¯¯¯x+n+12
