Or and And Problems

• or probability problems involve
  • The word "or"
  • A single experiment
  • Two possible outcomes.
• A die is rolled, what is the probability of the value being even or greater than 4?
  • Notice, we perform the experiment once
  • We are interested in two sets.
  • Draw a venn diagram of the experiment
  • P(A or B) = P(A) + P(B) - P(A and B)
• Two events are mutually exclusive if it is impossible for the two events to occur simultaneously.
• and probability problems
  • Frequently involve the word "and"
  • Involve performing the experiment two or more times.
  • P(A and B) = P(A)× P(B).
  • When computing P(B) assume that A occurred.
• Two events are independent if the occurrence of either event in no way affects the probability of the occurrence of the other event.
• Do some problems.