Study on Sample Size of Candidates Oriented to Online Test

The sample size directly affects the accuracy of the item parameter estimation of the online test. We simulate several tests comprised of 5 items, 9 items, 21 items and 41 items with different difficulties. Then, the Monte Carlo method is used to simulate candidates' answers to test items by Rasch response model. From this, we calculate the error metric of the test item distribution under different sample sizes. By comparing the real data with simulation data, we find that the fitting effect is good.