Model Choice was a Del II funded project.
Model Choice is an online multiple-choice system which presents 10 questions with configurable difficulty to a student. A particular feature of this system is that the feedback to students is carefully setup rather than just a 'correct' or 'wrong' indication. An intranet is used to add questions to the system. Questions ask a student to choose the model which based fits the described situation. This implementation replaces an earlier version which was based on a single PC. The system can easily be setup on a Linux based (or other MySQL and PHP supporting) server. Follow the link for more information and download the software.
Follow this link to the live demonstration (you will need to contact us for a username and password for the student pages and administrator pages.)
The download files for this project have not yet been setup, however if you email us we will send you the PHP code and MySQL database tables along with instructions for installation.
Introduction for Lecturers and Tutors
Model Choice (c) is a web-based, computer-aided assessment system that tests users' knowledge of probability models, particularly which standard probability distributions are appropriate for use in particular circumstances and what assumptions are required in order for these distributions to be valid.
Each user session consists of a number of questions (10 by default), selected at random from a large pool of questions at the appropriate Level of Difficulty (1, 2, or 3 in increasing order of difficulty). All the questions are multiple-choice and have five possible answers. Once the user selects an answer, a message appears along with some informative, context-sensitive feedback. By default, when users select the wrong option(s) they are allowed one more attempt at the question by choosing from among the remaining options. (Staff with the necessary permissions may opt to vary this, and allow 1, 2, 3 or 4 attempts at each question.) A user who answers incorrectly on the last attempt allowed is told the correct answer. At the end of the session, users are told the number of questions they got correct first time, and the number they got correct (on all attempts).
There are three basic question types:
Type A: the user is expected to identify the most appropriate univariate probability distribution to use to model a random variable described in the question
Type B: the user is expected to identify the assumption underlying the use of the stated distribution that is not valid in the particular circumstances described in the question
Type C: the user is expected to identify the most appropriate probability distribution(s) to use to model two random variables described in the question - this might be two standard univariate distributions or one standard bivariate distribution
Levels of Difficulty are differentiated by two factors. First of all, by the question types covered: Type A questions only are used in Level 1; Type A and B questions in Level 2; Type A, B and C questions in Level 3. Secondly, users are expected to know about more distributions in order to work at the higher levels of difficulty; the default list given in this table may be amended by staff with the relevant permissions.
Introduction for Students
Each session consists of ten questions, selected at random from a large pool of questions at the appropriate Level of Difficulty. All the questions are multiple-choice and have five possible answers. You should read each question and the alternative answers carefully. When you are ready, use the cursor to select the answer(s) you think correct, then click on the Check answer button.
A message will appear, telling you whether your answer was right or wrong, and the option(s) you chose will be marked appropriately (
or 
). If your first attempt is wrong, you can have a second try at the question, but if you are wrong again then you will be told the correct answer. You must then move on to the next question by clicking the Next question button. At the end of your session, you will be told the number of questions you got correct first time, and the number you got correct (first or second time).
Your tutor might have told you which Level of difficulty to attempt. If not, then before choosing a Level you might want to look at this table in order to find out which probability distributions are tested at which Level.