Item Analysis - Assignment Example

Download file to see previous pages This information needs to be interpreted in context to the principles on the basis of which the test was designed. A test that was given at the beginning of a course simply to assess which concepts a class was familiar with would be expected to have a positive skew; as there would be fewer items that students would be able to answer. On the other hand; if this test was given to assess mastery or proficiency; these scores would indicate that a number of course goals were not met. If the test were given in order to choose a few individuals who are proficient in very advanced concepts; it would be acceptable that a majority of scores are clustered towards the lower half; as only a few individuals would qualify by getting higher scores.It is also necessary to assess if these results are caused by a few erroneous or confusing items. This may be done by evaluating the trends seen for each item. A competency test typically contains a few simple items, a few difficult items and a few items with moderate difficulty. A speed test, on the other hand, requires all items to be similarly difficult. For a competency test; it is necessary that we choose items that not only have different levels of difficulty; but also discriminate between individuals who are able to solve it and those who are not. A good item would typically help us in understanding how well the individual test taker has mastered the individual concept while also helping us differentiate those who did master the concept from those who did not....
Also; the Alpha coefficient is affected by the length of the test; with the reliability being higher and more trusted for a longer test than a shorter one. The given test is only 10 items long; and this may compromise the reliability to some extent. The skewed scores also present other concerns. The Standard Error of Skewness for this test may be calculated by using the Tabachnick & Fidell’s (1996) formula . This provides us with a SES value of 0.245. If we define the acceptable limits within which the value of skewness may fall as being between 2 SES both sides of zero; then we may accept a value that falls between – 0.49 and + 0.49. the obtained value of + 0.78 is well outside these limits, indicating that there is a positive skew to the scores and a significant clustering of scores towards the lower side of the scale. This information needs to be interpreted in context to the principles on the basis of which the test was designed. A test that was given at the beginning of a course simply to assess which concepts a class was familiar with would be expected to have a positive skew; as there would be less items that students would be able to answer. On the other hand; if this test was given to assess mastery or proficiency; these scores would indicate that a number of course goals were not met. If the test were given in order to choose a few individuals who are proficient in very advanced concepts; it would be acceptable that a majority of scores are clustered towards the lower half; as only a few individuals would qualify by getting higher scores. It is also necessary to assess if these results are caused by a few erroneous or confusing items. This may be done by evaluating the trends seen for each item. A ...Download file to see next pagesRead More