Graded Quiz: Convolutional Neural Network Development :AI Capstone Project with Deep Learning (IBM AI Engineering Professional Certificate) Answers 2025
1. Which metric should Jane use to measure how well the model distinguishes between classes?
❌ Mean Squared Error
✅ AU-ROC (Area Under ROC Curve)
❌ Model accuracy
❌ Cross-entropy loss
Explanation:
AU-ROC evaluates how well the model separates classes across all thresholds, making it ideal for classification performance assessment.
2. What key component must Liam include in a CNN model for image classification?
❌ Dropout layers to increase model capacity
❌ Recurrent layers to capture temporal sequences
✅ Convolutional layers to extract spatial features
❌ Batch normalization layers to reduce model size
Explanation:
Convolutional layers are the core of CNNs, extracting spatial patterns such as edges, textures, and shapes in images.
3. What should the AgriTech team do first when building a CNN classifier in Keras?
❌ Compile the CNN model
✅ Preprocess the dataset to ensure all images are the same size
❌ Initialize the CNN model architecture
❌ Train the CNN model
Explanation:
All images must be resized and normalized before feeding them into the model; preprocessing is always the first step.
4. Why is HeUniform() used as a kernel initializer?
❌ It regularizes the model with L2 norms
✅ It initializes weights suited to ReLU-based activations
❌ It schedules the learning rate automatically
❌ It freezes pretrained ImageNet weights
Explanation:
He initialization prevents vanishing/exploding gradients and works best with ReLU or variants.
5. Why is torch.no_grad() used during validation?
✅ To disable gradient calculation, saving memory and computation
❌ To randomize batch order
❌ To reset model weights
❌ To enable GPU acceleration
Explanation:torch.no_grad() ensures no gradients are tracked, making evaluation faster and more memory-efficient.
6. Why is F1 Score preferred for highly imbalanced datasets?
❌ It considers only true positives and true negatives
❌ It measures area under the precision-recall curve
✅ It balances precision and recall, focusing on minority-class performance
❌ It is threshold-independent like ROC-AUC
Explanation:
F1 is the harmonic mean of precision and recall, giving a fairer performance measure when classes are imbalanced.
7. How can you generate a detailed summary with per-class precision, recall, and F1?
❌ accuracy_score
✅ classification_report
❌ roc_curve
❌ confusion_matrix
Explanation:classification_report outputs precision, recall, F1-score, and support for each class.
🧾 Summary Table
| Q# | Correct Answer | Key Concept |
|---|---|---|
| 1 | AU-ROC | Class-separation ability |
| 2 | Convolutional layers | Spatial feature extraction |
| 3 | Preprocess the dataset | CNN pipeline order |
| 4 | HeUniform | Weight initialization for ReLU |
| 5 | torch.no_grad() | No gradients during evaluation |
| 6 | F1 Score | Handling imbalance |
| 7 | classification_report | Per-class metrics |