A sample space consists of four sample points S1, S2, S3, and S4, where P1S12 = .3, P1S22 = .3, P1S32 = .2, and P1S42 = .2.

a. Show that the sample points obey the two probability LO5 rules for a sample space.

b. If an event A = 5S1, S46, find P(A).