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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:

  • ❌ Generate new data from noise

  • ❌ Classify images

  • ❌ Detect anomalies

  • 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:

  • ❌ Dimensionality reduction

  • Adding noise to data in multiple steps

  • ❌ Generating data

  • ❌ Clustering

Explanation:
Diffusion forward pass gradually destroys structure by adding noise.


3. Question 3

Common unsupervised dimensionality reduction method:

  • Principal Component Analysis (PCA)

  • ❌ Decision trees

  • ❌ K-means

  • ❌ Linear regression

Explanation:
PCA projects data into lower-dimensional space using variance.


4. Question 4

Purpose of the bottleneck layer:

  • ❌ Classification

  • ❌ Generate new samples

  • Lower-dimensional representation

  • ❌ Final reconstruction

Explanation:
The bottleneck compresses the data into the smallest latent space.


5. Question 5

Common application of diffusion models:

  • ❌ Language translation

  • ❌ Stock prediction

  • ❌ Marketing segmentation

  • Enhancing image resolution / denoising

Explanation:
Diffusion models excel at image generation and denoising.


6. Question 6

Primary function of GAN discriminator:

  • ❌ Classify categories

  • Distinguish between real and fake samples

  • ❌ Generate samples

  • ❌ Reduce dimensionality

Explanation:
Discriminator = binary classifier (real vs fake).


7. Question 7

TensorFlow-supported clustering algorithm:

  • ❌ CNNs

  • K-means algorithm

  • ❌ Linear regression

  • ❌ RNNs

Explanation:
K-means is provided in TF Addons and other libraries.


8. Question 8

Typical activation function in GAN discriminator output:

  • ❌ Tanh

  • ❌ ReLU

  • ❌ Softmax

  • Sigmoid

Explanation:
Sigmoid gives a probability of real vs fake (binary output).


9. Question 9

Why noise is added to generator input?

  • ❌ Increase discriminator speed

  • Simulate real-world variation

  • ❌ Reduce dataset size

  • ❌ Make discriminator’s job easier

Explanation:
Random noise ensures diverse sample generation.


10. Question 10

Main goal of training a GAN:

  • ❌ Improve classification accuracy

  • ❌ Cluster data

  • ❌ Reduce training time

  • 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