More Statistics on Sacramento Housing

In a previous post, I showed a pretty simple regression analysis of housing prices and house size for my Zip code. The zip code was used as an easy way to include location in the output. Using PostGIS and geographic data from the City of Sacramento, this post will show a regression analysis ( using the R statistical programming project) using the city’s designated neighborhoods. The raw data real estate data comes from the Sacramento Bee. After describing the model, I’ll apply it the last few months of home sales (not used in developing the model), and see how well it does at predicting results.    Continue reading

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A Real World Example of A/B Website Testing

A/B testing has gained a lot of interest in recent years as a practical method for improving the results from websites.  My business partner and I produced a mobile application, RecallCheck that relied on a database we created from FDA and USDA websites.  During our project, the FDA introduced a new website for reporting food related issues called the:  Reportable Food Registry.  For our purposes (using a mobile phones to scan bar codes), the result we most cared about was the quality and quantity of UPC codes.  Below is a detailed statistical analysis of before and after the FDA made it’s changes with regard to the quantity of UPC codes included in published recall notices.   While our interest was the UPC codes, the same process can be applied to any change on a website. Continue reading