Slide 10 of 25
Notes:
- On a die what is the probability of rolling a 2? On a given roll, the total number of possible observations is six (that is, 1, 2, 3, 4, 5, and 6). There is only one 2 on a die and hence only one possible observation favoring the event “2”. The probability is 1/6 or .17.
- If one draws one card at random from a standard deck, the probability of drawing an ace is 4/52 or .08. There are 52 possible observations, of which 4 favor an ace
- Probability of an impossible event is always 0. The probability of rolling an 8 on a single die is 0 because the number of observations favoring an “8” is 0. It follows that 0/6=0.
- The probability of a completely certain event is always 1.00
- If we flip a coin ten times, it is unlikely that the coin will come up heads exactly 5 times and tails the other 5. As we continue to flip the coin, then across a large number of flips, the number of heads relative to number of total flips will approach ½ or .50.
