Computer Assisted Assessment: How many questions are enough?

@misc{citeulike:530751, abstract = {Currently many universities make use of computer assisted assessment (CAA) as part of student assessment. Often these assessments take the form of a test where each question is randomly selected from a bank of alternatives. In this situation, the number of possible tests can be very large. For example, a test may have five questions and for each question there may be a bank of ten alternatives. The number of possible tests would be 105. This paper addresses the issue of how many tests, on average, need to be generated before all available questions have appeared at least once. By means of probability theory and the use of a computer algebra package, results are generated for a number of typical situations. Some surprising results are reported. For the example quoted above, it is found that, on average, only forty-three tests need to be generated before all available questions will have appeared at least once. The implications of these results, with reference to plagiarism, are discussed. Recommendations on how to reduce the possibility of plagiarism are provided.}, author = {Cornish, Rosie and Goldie, Charles and Robinson, Carol }, citeulike-article-id = {530751}, keywords = {caa}, month = {February}, posted-at = {2006-03-03 23:59:14}, priority = {2}, series = {Maths CAA Series: Feb 2006}, title = {Computer Assisted Assessment: How many questions are enough?}, url = {http://mathstore.ac.uk/articles/maths-caa-series/feb2006/}, year = {2006} }

TY - GEN ID - citeulike:530751 L3 - citeulike-article-id:530751 TI - Computer Assisted Assessment: How many questions are enough? SE - Maths CAA Series: Feb 2006 N2 - Currently many universities make use of computer assisted assessment (CAA) as part of student assessment. Often these assessments take the form of a test where each question is randomly selected from a bank of alternatives. In this situation, the number of possible tests can be very large. For example, a test may have five questions and for each question there may be a bank of ten alternatives. The number of possible tests would be 105. This paper addresses the issue of how many tests, on average, need to be generated before all available questions have appeared at least once. By means of probability theory and the use of a computer algebra package, results are generated for a number of typical situations. Some surprising results are reported. For the example quoted above, it is found that, on average, only forty-three tests need to be generated before all available questions will have appeared at least once. The implications of these results, with reference to plagiarism, are discussed. Recommendations on how to reduce the possibility of plagiarism are provided. KW - caa AU - Cornish, Rosie AU - Goldie, Charles AU - Robinson, Carol PY - 2006/02// UR - http://mathstore.ac.uk/articles/maths-caa-series/feb2006/ ER -