What does error guessing rely on during testing?

Error guessing is a testing technique that heavily relies on the tester's experience and intuition to anticipate where defects might exist in the application. This approach involves using previous knowledge gained from past projects, familiarity with similar systems, and an understanding of common error patterns to identify high-risk areas within the software.

When testers utilize error guessing, they apply their insights about potential weak points in the software, allowing them to create test cases that are more likely to uncover hidden issues. This method is particularly useful in exploratory testing, where formal documentation may be minimal, and a tester's judgement can lead to the discovery of defects that standard test scripts might overlook.

The other options focus on methods that do not directly leverage the tester’s experiential knowledge. Predefined test scripts follow a specific set of instructions and may not account for the unpredictable nature of defects. Feedback from end-users can provide valuable insights but is not part of the immediate testing phase. Automated testing tools are helpful for consistent and repeatable testing but don’t adapt to human intuition and the subtle understanding of where errors are likely to occur. Thus, the reliance on experience to anticipate potential defects distinctly characterizes error guessing.