# The Construction of Mathematics Diagnostic Test on the Conic Section for Tenth Grade Students

## Authors

• Wilawan Sangthong M.Ed. Student in Educational Research and Evaluation, Pibulsongkram Rajabhat University
• Phutcharawalai Meesup Faculty of Education, Pibulsongkram Rajabhat University
• Anu Jarernvongrayab Faculty of Education, Pibulsongkram Rajabhat University
• Punnawit Baikularb Faculty of Education, Pibulsongkram Rajabhat University

## Keywords:

Diagnostic test, The test to investigate defects, Conic section

## Abstract

The objectives of this research were: to investigate the defect on studying mathematics. Construct and to find the quality of the mathematics diagnostic test and study the defect on the conic section for tenth-grade students. The sample group used in this research were 436 tenth-grade students at Chalermkwansatree school,  which was selected by Sample Random Sampling. The research instruments were: 1) the test to investigate the defect and the mathematics diagnostic test for to be used to diagnose defects in students' answers. The results showed that: 1. In investigate the defect of the mathematics on the conic section which were able to point out students' defects. 2. The result of the construction of the diagnostic test and quality of the test showed the index of item objective congruence (IOC) with 0.67 - 1.00. The quality of the test showed the item difficulty (p) between 0.42 - 0.78 and the item discrimination (r) with 0.33 - 0.73. The test reliability was 0.85. The Standard Error of measurement was 2.43. 3. The results from the defect analysis that the students gave wrong answers. found that the students had the most deficiencies as follows: In the circle, the most defect of the students was misremembering the formulas and confusing the sign of radius for 26.21 percent, 16.24 percent of students remembered the formula wrong because they weren't squared at . In the oval, the most defect of the students was misremembering the formulas for finding the Latus rectum length for 20.80 percent, 15.15 percent of students distributing perfect square incorrectly or miscalculating. In the parabola, the most defect of the students was miscalculating the C value for 18.85 percent, 16.81 percent of students did not understand how to find the C value and directrix equation. In the hyperbola, the most defect of the students was representing the value of a, b and c wrong for 27.64, 19.52 percent of students cannot remember the constructing asymptomatic equations.