 Hi and welcome to the session. Let us discuss the following question. Question says, complete the following statements. First part is probability of an event E plus probability of the event not E is equal to dash. Let us now start with the solution. First of all let us understand that for any event E, P E that is probability of an event E plus P E bar that is probability of the event not E is equal to 1. Here E bar stands for not E, E and E bar are called complementary events. So from this expression we get probability of an event E plus probability of the event not E is equal to 1. So we can fill in this blank 1. This is our required answer. This completes the session. Hope you understood the solution. Take care and have a nice day.