The Number of Copies Sold of a Newsmagazine Varies from Week

Essay

The number of copies sold of a newsmagazine varies from week to week. Empirical
data gathered over many years suggest the following distribution of x = weekly sales
(rounded to the nearest million.) What is the mean of this distribution? $$\begin{array} { | c | c | c | c | c | } \hline x & 0 & 1 & 2 & 3 \\\hline P ( x ) & 0.15 & 0.25 & 0.40 & 0.20 \\\hline\end{array}$$