Abstract
This paper examines the problem of using statistical methods in the quality monitoring system of level language tests based on TOEFL, FCE and CAE materials. The majority of teachers and experts in qualimetry in general and educational qualimetry in particular are inexperienced which makes the use of test diagnostics at all stages of the learning process extremely challenging. The proposed approach involves the use of test diagnostics at every stage of the learning process to ensure accurate results. The quality of test tasks can be determined and the reliability coefficient of the tests can be calculated by employing experimental verification data and probabilistic factors. The statistical analysis of the results allows for the identification of qualitative characteristics of the test and provides insights into the heterogeneity of the subjects. This approach enables the grouping of subjects into homogeneous groups and ensures the adequacy of tests in a specific educational environment. This research employs the control cross-sectional analysis technique to identify areas of deficiency in understanding, ascertain the educational attainment of students and gauge their requirements. This method creates strategies to fill in any knowledge gaps and provides personalized support. Statistical methods are used in this research to collect, assess and analyse both quantitative and qualitative data.