Misc

Despite the recent unveiling of the new iPad mini , I would maintain that  Google's Nexus 7 tablet represents superior value for money. Granted it weighs a little more and lacks a front camera, but it's over £100 cheaper and that includes a quad-core processor! But there lies a fatal flaw. While the likes of Apple and Amazon have customer service down to a fine art, Google appears to be living on another planet.  Imagine an Amazon order that arrived broken, faulty or late. In almost every case, they would immediately despatch a replacement or issue a refund. Problem solved. My recent experience with Google has taken over a month to reach a similar conclusion. Part 1: The Order* I placed an order for a Google Nexus 7 Tablet on the 18th of September. Money was taken from my account and my tablet dispatched with an accompanying TNT tracking number. Unfortunately, this tracking number was invalid. After several days I phoned Google ...

Simple statistical concepts include the mean, median, standard deviation, and percentiles. These are useful for summarising data. Except these summary statistics are only useful under certain circumstances. When basic assumptions are not met, then any conclusions based on simple summary statistics are likely to be inaccurate. Unable to give a hint as to what is wrong, the numbers can often look perfectly reasonable. Lets consider a sample of 64 reaction time observations (in milliseconds): Mean = 387ms Median = 340ms These look ok, until you view the distribution, which is not unimodal.  Despite being a staple in data visualisation, histograms can often be a poor method for determining the shape of a given distribution because they are strongly affected by the number of bins used. For example, visualising the same data with only four bins can make the same observations appear normally distributed. Similarly, a box-plot can also hide data irregulari...