Data Science with Python Certification Data Science with Python (Basic) 4

Question 1

What is the purpose of StandardScaler in scikit-learn?

Accepted Answer

Transforms features to have zero mean and unit variance

Answer

StandardScaler standardizes features by removing the mean and scaling to unit variance (z-score normalization).

Question 2

Which of the following correctly reads a CSV file into a pandas DataFrame?

Accepted Answer

pd.read_csv('file.csv')

Answer

pd.read_csv() is the standard pandas function for parsing a comma-separated values file into a DataFrame.

Question 3

What does the term 'overfitting' mean in machine learning?

Accepted Answer

The model learns training data too well and fails to generalize to new data

Answer

Overfitting occurs when a model memorizes training data noise, resulting in high training accuracy but poor performance on unseen data.

Question 4

In Python, what does the zip() function do when applied to two lists?

Accepted Answer

Pairs elements from both lists into tuples, stopping at the shortest list

Answer

zip() aggregates elements from multiple iterables into tuples, stopping when the shortest iterable is exhausted.

Question 5

Which NumPy function returns the indices that would sort an array?

Accepted Answer

np.argsort()

Answer

np.argsort() returns the integer indices that would sort the array, not the sorted values themselves.

Data Science with Python Certification Practice Test