Funded by NCI, Gamma is software for statistical inference from spatial data such as that used in Geographic Information Systems. It uses location models and spatial Monte Carlo methods to fully specify the spatial sampling space. This provides three capabilities:
Gamma software is currently under development at BioMedware, although it will soon be released commercially. It has been used heavily by students in the past: for example,
You (and a partner, if possible!) will work through exercises demonstrating several different proximity and distance metrics. In the final exercise you will use Gamma to analyze a putative clustering of breast cancer cases by calculating your own custom spatial statistic (Gamma product) and comparing it to an appropriate empirical distribution.
UMich Students: save gamma.zip and extract Gamma to c:\temp
Download the Gamma software and extract it using WinZip (if necessary, download WinZip):
UMich students: The demo version is a time-expiring executable; that is, it is good for a limited time only (sound like a commercial?). You can use this copy of Gamma to do your project analysis, or download another copy at any time. The password required to run this beta version is epid624.
You will need to (finally!) compute your gamma statistic by generating some Monte Carlo runs (so far, you've breezed past the Monte Carlo screen). Proceed as you did for the previous examples:
View -> View Output Session Window
, and
Plot -> Distribution
Interpret your results. Did you make good choices of Proximity and Distance metrics? Can you do better? What does the p-value mean?
UMich Students: A note for your projects: Gamma does not yet read in ArcView shape files, so you'll need to convert them to Atlas bna files first. If you need help with this, let your instructors know.
Website maintained by Andy Long. Comments appreciated.