Describe what is meant by a “test norm” and why we get norms for a test.

          A test norm is data that is used for determining the relative rank of an individual in terms of psychological testing. Norms are a means of translating raw scores into a type of normed score (Hogan, 2007). A raw score is basically the result of one’s test responses. One's raw score is compared with other individual's scores of the norm group to determine where an individual ranks which enables the effective assessment of an individual (Hogan, 2007).    

What are the strengths and weaknesses of percentile norms, score norms, and developmental norms?

           A percentile refers to a particular point on a scale which is below a set percentage of the cases falls (Hogan, 2007). Strengths of percentile norms is that they are easily understandable and explainable. The weaknesses of percentile norms is that they are inequality. Score norms are basically standard scores, which are a type of norm often used with psychological and educational tests (Hogan, 2007). Strengths are that there are many extensively used versions and countless other versions. Weaknesses are that it can be difficult to convert raw scores into standard scores with a set manual. Developmental norms are created when a particular measured trait develops systematically with time (Hogan, 2007). Strengths of developmental norms is that  there is an attractiveness of their naturalness to their meaning and they provide a means to measure growth over multilevel tests (Hogan, 2007). Weakness of developmental norms is that they are only relevant to the variables that clearly display developmental patterns and their standard deviations are uncontrolled.   

Briefly describe the major sources of unreliability affecting test scores and the main factors influencing the magnitude of an internal consistency measure of reliability.

           The major sources of unreliability are test scoring, test content, test administration conditions, and personal conditions of the examinee; therefore, these four sources contribute to unsystematic variations in test scores (Hogan, 2007).  

Reference

Hogan, T. P. (2007). Psychological testing: A practical introduction (2nd ed.).  Hoboken, NJ: Wiley.