# mathematics

### cumsum ( rnorm(50), lend="butt", lwd=12, type="h" ) Cumulative…

December 8, 2010 |

cumsum ( rnorm(50), lend="butt", lwd=12, type="h" ) Cumulative sum of 50 draws from a normal distribution. File this under mysteries of the Central Limit Theorem. [Read more...]

### Central Limit Theorem A nice illustration of the Central Limit…

October 20, 2010 |

Central Limit Theorem A nice illustration of the Central Limit Theorem by convolution.in R: Heaviside 0,1,0) }HH [Read more...]

### Here is how to improve your charts, graphs, maps, and…

October 2, 2010 |

Here is how to improve your charts, graphs, maps, and plots: Erase non-data ink. Erase redundant data ink. Maximize the ratio of data to ink. Show data variation, not design variation. The surface area of graphical elements should be directly proportio... [Read more...]

### extrapolation and interpolation The most important lesson I…

May 25, 2010 |

extrapolation and interpolation The most important lesson I learned from this book:  regression is reliable for interpolation, but not for extrapolation.  Even further, your observations really need to cover the whole gamut of causal variables, inter... [Read more...]

### The Price of Calculation

March 15, 2010 |

In a world in which the price of calculation continues to decrease rapidly, but the price of theorem proving continues to hold steady or increase, elementary economics indicates that we ought to spend a larger and larger fraction of our time on calculation.1 Over the next ten years, I hope ... [Read more...]

### Top Five Open Source Projects of 2009

November 5, 2009 |

Every year, I single out what I think are the Top Five open source projects. This year, there's only one hold-over from previous years, and it's likely that I'm just going to give it a Lifetime Achievement Award and pick five others next year. 5. NetBe... [Read more...]
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