Slide 4 A Visualization Solution Becomes a Problem 1.5 million incidents per year Around 40 crime classifications Approximately 6900 sworn officers
Slide 5 A Classic Problem – The “Data Tornado” By Golly Toto, it’s a twister!
Slide 6 Where Do They Clump? From http://data.baltimoresun.com/crime/anne_arundel/accident-person-injured/?mode=heat (not HunchLab)http://data.baltimoresun.com/crime/anne_arundel/accident-person-injured/?mode=heat
Slide 7 ? What We Really Want to Know – How are the Densities CHANGING? Crimes 8/16/2008 – 8/22/2008 Crimes 8/23/2008 – 8/30/2008
Slide 8 How Do We Figure out Density Change? Take an area or *many* areas to evaluate Use statistics to compare historical norms to current densities But… how? Call crimes balls in a bag.
Slide 9 That’s Right, Balls In a Bag That’s Right, Balls in a Bag A bag has 20 black balls and 80 white balls. Choose 5 at random. What is the chance of getting 3 black balls? Vary number of balls chosen and you get a Hypergeometric Distribution