1. FALSE PRECISION
                                       
 
"THE ODDS ARE 69.3 TO ONE AGAINST US"
    Eight Rules

2. Base Rate Fallacy

3. Correlation Not Causation

4. Single Variable

5. Substantial Differences

6. Longitudinal Study

7. Different From Chance

8. Dose-Response 		 
  • A Common Theme in Science Fiction

  • One Of The Characters Expresses An Opinion

  • About Their Odds Of Success

  • Usually to 3 or 4 significant figures

    Is this realistic?
    		•  
       
     
     
  • Let's try this with a coin flip

  • Calculate heads and tails for fair coin

  • How easy is it to establish whether coin is fair?
    		•  
      TOP
     
     
      Flip the coin four times; expect two heads and two tails.   What do you actually get?

    There are sixteen (24) possible outcomes; six have two heads and two tails.   Ten (62%) DO NOT.   Do more flips help?

    Four flips => 10/16 => 62% NOT half heads

    Six flips => 44/64   =>   59% NOT

    Eight flips => 186/256 =>   83% NOT

    Ten flips => 972/1024   =>   75% NOT     		  HHHH   TTTT  
    THHH   HTTT  
    HTHH   THTT  
    HHTH   TTHT  
    HHHT   TTTH  
    TTHH   HHTT  
    THTH   HTHT  
    THHT   HTTH  
     
     
     
    This is far from trivial.   And it's a relatively simple problem!!

    If it's this hard to determine whether a coin is fair, how difficult will it be to calculate the odds of successfully negotiating an asteroid field?     		 
      TOP Next