4.There are 1000 patients at a hospital. Among the 1000 patients, 250 patients have Chills, and 300 patients have Fever. 100 patients have both chills and fever. Let C be the event that a randomly selected patient has Chills, and F be the event that a randomly selected patient has Fever. (Show all work. Just the answer, without supporting work, will receive no credit.)

1. (a)Provide a written description of the complement event of (C OR F).
2. (b)What is the probability of the complement event of (C OR F)?