Learning Java

I am crap at marketing. In a perfect world, I'd never have to sell anything. I'd just be. But the world is not perfect. And why waste time creating computer software if you can't sell it? One of the reasons I began the quest to learn Java was that the version of my software written in VB6 is sitting on 600 CD's, which now gather dust in my living room. I spent a year writing to, calling and visiting schools, but the revenue generated was barely compensation for the installation time, let alone marketing, let alone development. Out of 221 schools on the target list (essentially primary schools in the metropolitan area of Perth, Western Australia), 61 agreed to a meeting and a trial on at least one computer, and 16 actually paid for a full site license. The official price was $660, but I let some have it for half that, and I always threw in a day's worth of installation and training. I didn't charge for the two or three presale visits, and for ...

Following on from my last blog, the table below shows the raw scoring rates on two additional items, H and K. Item H is twice as hard as item I, and is only addressed by Student B. Item K is twice as easy as Item J and is only addressed by Student A. This scenario synthesises one which might be generated by a computer based adaptive arithmetic test , which presents more difficult items to more able students and easier items to less able students. Raw Rates Item H Item I Item J Item K Session Mean Student A 4 8 16 9.33 Student B 4 8 16 9.33 It Mean 4 6 12 16 9.33 From the table, the effect of the adaptive component of the computer based arithmetic test has been similar to that of a very good handicapper in a horse race. By presenting more difficult items to the more able student and easier items to the less able student, it has ...

In my blog of 25 August , I described some iterative transformations on scoring rate data from a computer based arithmetic test . I said I would report the results of further iterations, if I liked them , and from the time that has past it should be obvious to anyone reading this that I didn't. The transformations were based on what I called the scoring rate quotient (SRQ) . Essentially I divided the scoring rate for every item in every test session by the mean of all scoring rates for every item in every test session to produce the SRQ for individual session-item combinations and to calculate the mean SRQ for every session and for every item. To illustrate, imagine two students, A and B, addressing two items, I and J. Imagine in this case that Student B scores at twice the rate of Student A and that Item I is twice as difficult as Item J. The raw scoring rates might look as follows: Raw Rates Item I Item J Session Mean Student A ...

The Web is a great boon to travellers. Where once you had to sit like a prune on a travel agents chair while they fiddled about for hours on a computer, now you can tailor make your own holiday from your own living room. As well as the vendor sites, there are these web sites, which purport to search for and sort whatever you are looking for. At the top of the list are what purport to be the best bargains, and the unwary might simply click on these and look no further. If you type UK car hire into Google, an array of sites like this one appear high on the list. It invites you to enter dates, a pickup location, and a car type, and then runs a search "of up to 40 companies" for you. A couple of things should be born in mind when interpreting these results. One is that only 4 companies actually have representation at the airport. From memory these are Avis, Budget, Europcar, and Hertz. The others are scattered through West London, take ages to pick you up, and are helli...