question_answer

Let\[{{x}_{1}},{{x}_{2}},.....,{{x}_{n}}\]be n observations such that \[\Sigma x_{i}^{2}=400\]and\[\Sigma {{x}_{i}}=80\]. Then, a possible value of n among the following is     AIEEE  Solved  Paper-2005

A) 12                          

B)        9                             

C)        18                          

D)        15

Correct Answer: C

Solution :

Using the inequality, AM of m th power > m th power of AM, if Then