Abstract: This paper issues a model of test assignment based on normal distribution, according to commonly used algorithms of automatic assignment. In this model, test space is divided into different difficulty levels of test set, then the difficulty levels are distributed according to the normal distribution. The model has a simple structure, fast, efficient, focused topics and feasibility of good features and has been applied to the subjective test examination on computer programming system.

Key words: normal distribution, item difficulty, normally distributed random numbers, discrete