Study On Application Of Normal Distribution In Score Ranking And Adjusting

Test score is key to evaluate learning result, and test score ranking is regarded as a valuable reference for a student to set a studying objective. Hence, it’s vital to manipulate test score ranking accurately and scientifically. With application of normal distribution theory and basis on concept of quantile involved in statistics, the approach to test score ranking discussed in this thesis is to apply normal upper percentile given that the population is normally distributed, called NUP approach in brief. Also, it focuses on illustrating the approach to be scientific, advantageous and meaningful in reality respectively through true instances.Additionally in this paper, it studies on the phenomenon existing in the score adjustment method for college entrance examinations on elective subjects in Shanghai, that is,"less adjustment on scores at top and bottom level, while more adjustment on scores at intermediate level". It states the potential side effect resulted from this score adjustment method, and puts forward to NUP approach to be applied in score adjustment. As well, NUP approach is demonstrated to be more scientific and advanced in contrast to the results from the chosen method in college entrance examinations and in daily school life separately.At last, it points out the limitation of using NUP approach. That is, when population of scores has small size, and non-normally distributed, the approach may cause bias to some extent. In this case, percentile ranking which is more general can be used instead of NUP approach as supplement.