1 Binary option. 63 DTE binary PUT with strike of 80 is priced at 15c. What is annual sigma? SO is 100. Binary option pays $1 if expires ITM, and $0 otherwise. Binary put is priced at F(z-x), ie the CDF value. Binary call is priced at 1-F(z-x) first figure out where z-x is relationship b/w z-x and SO and X sigma_T = (X-SO)/z-x sigma_T = sigma * sqrt(T)