1. Language is a system of arbitrary vocal symbols used for human __________ A. contact B. communication C. relation D. community 2. Which of the following words is entirely arbitrary? A. tree B. typewriter C. crash D. bang
1、解: (1) P{只订购 A 的}=P{A(B∪C)}=P(A)-{P(AB)+P(AC)-P(ABC)}=0.45-0.1.-0.08+0.03=0.30. (2) P{只订购 A 及 B 的}=P{AB}-C}=P(AB)-P(ABC)=0.10-0.03=0.07 (3) P{只订购 A 的}=0.30