Chapter 8 - Section 8.3 - Measures of Central Tendency - Exercises - Page 576: 19

E(x) = 1

H = head, T = tail P(x=0) = $P(H)\times P(H)$ = $\frac{1}{2}\times\frac{1}{2}$ = $\frac{1}{4}$ P(x=1) = $P(H)\times P(T)+P(T)\times P(H)$ = $\frac{1}{2}\times\frac{1}{2}+\frac{1}{2}\times\frac{1}{2}$ = $\frac{1}{2}$ P(x=2) = $P(T)\times P(T)$ = $\frac{1}{2}\times\frac{1}{2}$ = $\frac{1}{4}$ E(x) = $0(\frac{1}{4})+1(\frac{1}{2})+2(\frac{1}{4})$ = 1