• Probability generaly refers to an event whose outcome is unknown – if we would know the outcome we do not need to check probability. Probability tells us how often some outcome is likely to occur when an experiment is repeated.
  • Conditional probability – tells us probability of some outcome given that another outcome has occured.
  • trials – probability is inseparably connected with outcome of trials (experiments / observations)
  • events – event is outcome of a trial
  • union – several simple events create a compound event
  • sample space – set of all possible elementary outcomes of a trial – set of events
  • intersection – of two or more simple events creates a compound event that can occure only if all the simple events occur
  • complement of an event – basically “all around events which is not event”
  • mutual exclusivity – events which cannot occure together are mutually exclusive
  • independent events – outcomes of different events have no relationships
  • permutations – all the possible ways elements in a set can be arranged + order is important
  • combinations – like permutations but order of elements is not significant