Discrimination Index Calculator
Introduction
Statistical analysis often requires measures to assess the discriminatory power of test items or questions. One such measure is the Discrimination Index (DI), which indicates how well a test item discriminates between high and low achievers. Calculating DI is crucial in educational research, psychometrics, and various other fields. To facilitate this calculation, we present a simple Discrimination Index Calculator.
How to Use
- Input the number of students who answered the item correctly (H) and incorrectly (L).
- Input the total number of students who took the test (N).
- Click on the “Calculate” button to obtain the Discrimination Index.
Formula
The Discrimination Index (DI) is calculated using the following formula:
Where:
- H = Number of students who answered the item correctly.
- L = Number of students who answered the item incorrectly.
- N = Total number of students who took the test.
Example Solve
Let’s say in a class of 50 students, 40 answered a particular test item correctly, and 10 answered incorrectly. To calculate the Discrimination Index:
FAQs
Q: What does the Discrimination Index indicate?
A: The Discrimination Index measures how effectively a test item differentiates between high and low achievers. A higher DI suggests better discrimination.
Q: What is considered a good Discrimination Index value?
A: Typically, a Discrimination Index above 0.3 is considered good, indicating strong discrimination.
Q: Can the Discrimination Index be negative?
A: Yes, it is possible for the Discrimination Index to be negative if more low achievers answer the item correctly than high achievers.
Conclusion
The Discrimination Index Calculator provides a straightforward way to assess the discriminatory power of test items. By inputting the number of correct and incorrect responses, educators and researchers can gain valuable insights into the effectiveness of their assessments.