Question

The arithmetic mean of 1, 2, 3, ... , n is
(a)n+1/2
(b)n-1/2
(c)n/2
(d)n/2+1

Answer 1

SOLUTION :  

The correct option is (a) : (n +1)/2

Given : Observations are 1,2,3,.....n  

First n natural numbers are : 1,2,3.........n  

MEAN = Sum of all the observations/ Total number of observations

MEAN = (1 + 2 + 3 + ……+ n )/n

MEAN = (n/2 (n + 1)) / n  

[The sum of the first n natural numbers : Sn = n/2 (a + l ) = n/2(1 + n) = n/2(n +1)]

MEAN =  (n/2 (n + 1)) × 1/n  

MEAN  = (n + 1) /2  

Hence, the arithmetic mean of 1,2,3,...n is (n + 1) /2 .

HOPE THIS ANSWER WILL HELP YOU……

Answer 2

answer correct option is (a) n+1/2.......