Week 4 Quiz :Sequences, Time Series and Prediction (DeepLearning.AI TensorFlow Developer Professional Certificate) Answers 2025
1. Question 1
Python library used to read CSV files?
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❌ py_csv
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❌ py_files
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❌ CommaSeparatedValues
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✅ csv
Explanation:
Python’s built-in csv module is used for reading/writing CSV files.
2. Question 2
Why is MAE good for accuracy in time series?
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❌ It punishes larger errors
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✅ It doesn’t heavily punish larger errors like squared errors do
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❌ Only counts positive errors
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❌ Biases toward small errors
Explanation:
MAE treats all errors linearly → good when you don’t want large errors exaggerated (unlike MSE).
3. Question 3
Expected input shape for a univariate time series to Conv1D?
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✅ (window_size, 1)
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❌ (1, window_size)
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❌ ()
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❌ (1,)
Explanation:
Conv1D expects:
(timesteps, features)
Univariate = 1 feature.
4. Question 4
Correct way to cast column 2 to float?
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❌ Convert.toFloat(row[2])
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❌ float f = row[2].read()
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✅ float(row[2])
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❌ You can’t
Explanation:
Casting strings from CSV to float uses:
value = float(row[2])
5. Question 5
How to add a 1-D convolution layer?
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❌ ConvolutionD1
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❌ 1DConvolution
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✅ Conv1D
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❌ 1DConv
Explanation:
Correct Keras layer:
tf.keras.layers.Conv1D(...)
6. Question 6
CSV file has a header you want to skip — what do you call?
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❌ reader.next
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✅ next(reader)
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❌ reader.ignore_header()
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❌ reader.read(next)
Explanation:next(reader) reads and discards the first line (header).
7. Question 7
Best neural network type for predicting time series like sunspots?
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❌ RNN/LSTM
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❌ Convolutions
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❌ DNN
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✅ A combination of all other answers
Explanation:
The best model blends:
✔ convolution for pattern extraction
✔ LSTM/RNN for temporal relationships
✔ dense layers for final prediction
🧾 Summary Table
| Q# | Correct Answer | Key Concept |
|---|---|---|
| 1 | csv | Reading CSV files |
| 2 | MAE doesn’t heavily punish large errors | MAE benefits |
| 3 | (window_size, 1) | Conv1D input shape |
| 4 | float(row[2]) | Type casting |
| 5 | Conv1D layer | Convolution for time series |
| 6 | next(reader) | Skipping headers |
| 7 | Combination model | Best architecture |