AI0-001 Machine Learning and Deep Learning Practice Question
A data scientist is building a classification model to detect fraudulent transactions. The dataset is highly imbalanced with only 1% fraudulent cases. Which approach should the scientist use to evaluate model performance most effectively?
⚠ Common exam trap
CompTIA often tests the misconception that accuracy is always the best metric for classification, but in imbalanced datasets, accuracy is a trap because it does not reflect performance on the minority class, leading candidates to overlook metrics like F1 score that directly address class imbalance.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
F1 score
In highly imbalanced datasets like fraud detection (1% positive class), accuracy is misleading because a model that predicts all transactions as legitimate would achieve 99% accuracy yet fail to detect any fraud. The F1 score (harmonic mean of precision and recall) is the most effective metric because it balances both false positives and false negatives, providing a single score that reflects the model's ability to correctly identify the minority class without being skewed by class imbalance.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
F1 score
Why this is correct
F1 score is the harmonic mean of precision and recall, providing a balanced measure for imbalanced datasets.
- ✗
Accuracy
Why it's wrong here
Accuracy is not suitable for imbalanced datasets as it can be high even if the model fails to detect fraud.
- ✗
Recall
Why it's wrong here
Recall only considers false negatives, not false positives, so it is insufficient alone.
- ✗
Precision
Why it's wrong here
Precision only considers false positives, not false negatives, so it does not fully capture model performance on fraud detection.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AI0-001 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AI0-001 exam.