Psikometri -norma-

NORMS Meaning Of Norm-Referencing An individual perfomance in any psychological and eduational test is recorded in terms of the raw scores. Raw scores are expressed in terms of different units, such as the number of trials taken within a specified period to reach a criterion; the number of correct responses given by the examinees; the number of wrong responses given; the total time taken in assembling the objects; and the like. Usually, there are two reference points that are applied in interpreting the test scores. The first way is to compare an examinee’s test score with the scores of a specific group of examinees on the test. This process is known as norm-referencing. When raw scores are compared with the norms, a scientific meaning emerges. Norms may be defined as the average perfomance on a particular test made by a standardisation sample. By standardiastion sample is meant a sample which is the true representative of the population and takes the test for the express purpose of providing data for comparison and subsequent interpretation of the test scores. For adequate representation the sample must include a cross-sectional representation of different part of the population. In order to compare the raw scores with the performance of the standardisation sample, they are converted into ‘derived scores’. There are two reason, first the derived scores provide occasion for direct comparison of the person’s own performances on different test, because they are expressed in the same units for different test. Second, the derived scores denote the person’s relative position in the standardiastion sample. The second way of interpreting a test score is to establish an external standard of criteria and compare the examinee’s test scores with it. This way is called criterion referencing. In a criterion-referenced test there is a fixed performance criterion. It means the criterion result measured from the group of examinee which given training and before training. If after training scores are better than the pretraining scores, the test can be considered as sensitive to the result or outcomes of the training. In other words, the test scores can be interpeted as an indication of increased skill or proficiency. There are three important thing of criterion referenced test : 1. The test is usually based upon a set of behavioral referents, which it intends to

measured. 2. The test represents the samples of actual behaviour or performance. 3. The performance on a criterion –referenced test can be explained in terms of predetermined cut-off scores.

Types of Norms and Test Scales The four commonly derived scores are age scores, grade scores, percentile scores, and standard scores. Accordingly, there are four types of norms-age norms, grade norms, percentile norms and standard score norms. A detailed critical discussion of each of these is given below.

1. Age-equivalent Norms -Age-equivalent norms are defined as the average perfomance of a representative sample of a certain age level on the measure of a certain trait or ability.

2. Grade-equivalent Norms -Like age-equivalent norms, grade equivalent norms are defined as the average perfomance of a representative sample of a certain grade or class.

3. Percentile Norms -Percentile norms are the most popular and common type of norms used in psychological and educational tests. A percentile norm indicates, for each raw score, percentage of standardisation sample the falls below that raw score.

4. Standard Score Norms -A norm which is based upon a standard score is know as astandard score tile norms is that here units of the scale are equal so that they convey the same meaning throughout the whole range of the scale.