Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Probability Powerpoint


Published on

Published in: Technology, Education

Probability Powerpoint

  1. 1. PROBABILITY! Notes Examples Sample Problems
  2. 2. Definition <ul><li>Probability is the measure of how likely something will occur. </li></ul><ul><li>It is the ratio of desired outcomes to total outcomes. </li></ul><ul><ul><li>(# desired) / (# total) </li></ul></ul><ul><li>Probabilities of all outcomes sums to 1. </li></ul>
  3. 3. Example <ul><li>If I roll a number cube, there are six total possibilities. (1,2,3,4,5,6) </li></ul><ul><li>Each possibility only has one outcome, so each has a PROBABILITY of 1/6. </li></ul><ul><li>For instance, the probability I roll a 2 is 1/6, since there is only a single 2 on the number cube. </li></ul>
  4. 4. Practice <ul><li>If I flip a coin, what is the probability I get heads? </li></ul><ul><li>What is the probability I get tails? </li></ul><ul><li>Remember, to think of how many possibilities there are. </li></ul>
  5. 5. Answer <ul><li>P(heads) = 1/2 </li></ul><ul><li>P(tails) = 1/2 </li></ul><ul><li>If you add these two up, you will get 1, which means the answers are probably right. </li></ul>
  6. 6. Two or more events <ul><li>If there are two or more events, you need to consider if it is happening at the same time or one after the other. </li></ul>
  7. 7. “And” <ul><li>If the two events are happening at the same time, you need to multiply the two probabilities together. </li></ul><ul><li>Usually, the questions use the word “and” when describing the outcomes. </li></ul>
  8. 8. “Or” <ul><li>If the two events are happening one after the other, you need to add the two probabilities. </li></ul><ul><li>Usually, the questions use the word “or” when describing the outcomes. </li></ul>
  9. 9. Practice <ul><li>If I roll a number cube and flip a coin: </li></ul><ul><li>What is the probability I will get a heads and a 6? </li></ul><ul><li>What is the probability I will get a tails or a 3? </li></ul>
  10. 10. Answers <ul><li>P(heads and 6) = 1/2 x 1/6 =1/12 </li></ul><ul><li>P(tails or a 5) = 1/2 + 1/6 = 8/12 = 2/3 </li></ul>
  11. 11. Experimental Probability <ul><li>An experimental probability is one that happens as the result of an experiment. </li></ul><ul><ul><li>(# of outcomes) / (# of trials) </li></ul></ul><ul><li>The probabilities we have done so far are “theoretical probabilities”, because there was no experiment. </li></ul>
  12. 12. Experiment <ul><li>Flip a coin 50 times, and write down what happens for each flip. </li></ul><ul><li>In the end, find the experimental probabilities by writing the how many times heads and tails occurred over the total number of trials (flips) </li></ul>