Find the mean of the variable x assuming following values:
1) 1,2,.......n with frequency as it's values.
2) the first n natural numbers.
3) 1^2,3^2,5^2,....(2n-1)^2.
4)2,4,6,...,2n.
5)2^3,4^3,6^3,.....(2n)^3.
6)1,2,.....n with frequency 1^2,2^2,.....n^2 respectively.
