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Week 3 Quiz :Natural Language Processing in TensorFlow (DeepLearning.AI TensorFlow Developer Professional Certificate) Answers 2025

1. Question 1

When stacking LSTMs, how do you feed the next LSTM in the sequence?

  • ❌ Ensure same number of units

  • ❌ Do nothing

  • ❌ return_sequences = True on all

  • ✅ return_sequences = True only on units that feed another LSTM

Explanation:
Only LSTM layers feeding into another LSTM must output a sequence → set return_sequences=True.


2. Question 2

How does an LSTM capture long-range meaning?

  • ❌ Load all words into cell state

  • ❌ They don’t

  • ✅ Earlier word values can be carried forward via the cell state

  • ❌ Shuffle words randomly

Explanation:
LSTMs maintain memory through a cell state that flows across time steps.


3. Question 3

Best way to avoid overfitting in NLP datasets?

  • ❌ LSTMs

  • ❌ GRUs

  • ❌ Conv1D

  • ✅ None of the above

Explanation:
Overfitting isn’t solved by architecture choice → use regularization, dropout, augmentation, more data.


4. Question 4

Which Keras layer allows LSTMs to read forward and backward?

  • ❌ Bilateral

  • ❌ Unilateral

  • ❌ Bothdirection

  • ✅ Bidirectional

Explanation:
Bidirectional() wraps an LSTM so it processes the sequence forward and backward.


5. Question 5

Why does sequence matter for semantics?

  • ❌ It doesn’t

  • ❌ Because order dictates their impact on meaning

  • ❌ Order doesn’t matter

  • ✅ Because the order in which words appear dictates their meaning

Explanation:
Word order changes meaning entirely:
“dog bites man” ≠ “man bites dog”.


6. Question 6

How do RNNs help understand sequence meaning?

  • ❌ They don’t

  • ❌ They shuffle the words

  • ❌ They look at whole sentence at once

  • ✅ They carry meaning from one cell to the next

Explanation:
RNNs pass hidden states between time steps → sequence-aware understanding.


7. Question 7

Output shape of a bidirectional LSTM with 64 units?

  • ❌ (128,1)

  • ❌ (128,None)

  • ❌ (None,64)

  • ✅ (None,128)

Explanation:
Bidirectional doubles the units:
64 forward + 64 backward = 128.


8. Question 8

Sentence = 120 tokens → Conv1D with 128 filters, kernel size = 5.
What is output shape?

  • ❌ (None, 120, 124)

  • ✅ (None, 116, 128)

  • ❌ (None, 116, 124)

  • ❌ (None, 120, 128)

Explanation:
Conv1D output length (no padding):
120 − 5 + 1 = 116
Filters = 128 channels.


🧾 Summary Table

Q# Correct Answer Key Concept
1 return_sequences=True for stacked LSTMs Stacking LSTMs
2 Cell state carries info LSTM long-range dependencies
3 None of the above Overfitting not solved by architecture
4 Bidirectional Forward + backward context
5 Sequence dictates meaning NLP semantics
6 Carry meaning between cells RNN sequence modeling
7 (None, 128) Bidirectional doubles units
8 (None, 116, 128) Conv1D output shape