Question

pls someone answer quickly with step by step explanation... best and quickest answer shall be marked as brainliest​

Answer 1

heya,

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 it helps you ❣️

brainlist please ❣️