Graded Quiz: Unsupervised Learning and Generative Models in Keras :Deep Learning with Keras and Tensorflow (IBM AI Engineering Professional Certificate) Answers 2025
1. Question 1
Primary goal of an autoencoder:
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❌ Generate new data from noise
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❌ Classify images
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❌ Detect anomalies
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✅ To compress and then reconstruct data
Explanation:
Autoencoders learn compact representations and try to rebuild the original input.
2. Question 2
In diffusion models, the forward process:
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❌ Dimensionality reduction
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✅ Adding noise to data in multiple steps
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❌ Generating data
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❌ Clustering
Explanation:
Diffusion forward pass gradually destroys structure by adding noise.
3. Question 3
Common unsupervised dimensionality reduction method:
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✅ Principal Component Analysis (PCA)
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❌ Decision trees
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❌ K-means
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❌ Linear regression
Explanation:
PCA projects data into lower-dimensional space using variance.
4. Question 4
Purpose of the bottleneck layer:
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❌ Classification
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❌ Generate new samples
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✅ Lower-dimensional representation
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❌ Final reconstruction
Explanation:
The bottleneck compresses the data into the smallest latent space.
5. Question 5
Common application of diffusion models:
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❌ Language translation
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❌ Stock prediction
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❌ Marketing segmentation
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✅ Enhancing image resolution / denoising
Explanation:
Diffusion models excel at image generation and denoising.
6. Question 6
Primary function of GAN discriminator:
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❌ Classify categories
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✅ Distinguish between real and fake samples
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❌ Generate samples
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❌ Reduce dimensionality
Explanation:
Discriminator = binary classifier (real vs fake).
7. Question 7
TensorFlow-supported clustering algorithm:
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❌ CNNs
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✅ K-means algorithm
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❌ Linear regression
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❌ RNNs
Explanation:
K-means is provided in TF Addons and other libraries.
8. Question 8
Typical activation function in GAN discriminator output:
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❌ Tanh
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❌ ReLU
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❌ Softmax
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✅ Sigmoid
Explanation:
Sigmoid gives a probability of real vs fake (binary output).
9. Question 9
Why noise is added to generator input?
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❌ Increase discriminator speed
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✅ Simulate real-world variation
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❌ Reduce dataset size
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❌ Make discriminator’s job easier
Explanation:
Random noise ensures diverse sample generation.
10. Question 10
Main goal of training a GAN:
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❌ Improve classification accuracy
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❌ Cluster data
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❌ Reduce training time
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✅ Generate realistic synthetic data
Explanation:
GANs produce new samples that mimic real data.
🧾 Summary Table
| Q# | Correct Answer |
|---|---|
| 1 | Compress + reconstruct |
| 2 | Add noise step-by-step |
| 3 | PCA |
| 4 | Lower-dimensional representation |
| 5 | Image denoising / enhancement |
| 6 | Distinguish real vs fake |
| 7 | K-means |
| 8 | Sigmoid |
| 9 | Simulate data variation |
| 10 | Generate realistic synthetic data |