Question 487750
You want to find the arithmetic mean of one 1, two 2's, ..., five 5's, which is essentially


*[tex \LARGE AM = \frac{1^2 + 2^2 + ... + 5^2}{1+2+3+4+5} = \frac{55}{15} = \frac{11}{3}]


since the sum of the entries is 1^2 + ... + 5^2 and there are 1+2+...+5 entries.