Question 1

You are working with a small dataset and want to assess your model's performance. Your colleague recommends using k-fold cross-validation. However, you are concerned about the reliability of the evaluation. What cross-validation technique would be most appropriate for your small dataset?

Options :

A : Leave-One-Out Cross-Validation (LOOCV)

B : Shuffle-Split Cross-Validation

C : Regular k-Fold Cross-Validation

D : Stratified k-Fold Cross-Validation

E : Time Series Cross-Validation

Answer: A

Question 2

You are working with a dataset that includes both categorical and continuous features. Which of the following feature scaling techniques would be most appropriate for scaling only the continuous features?

Options :

A : Min-Max Scaling

B : One-Hot Encoding

C : Label Encoding

D : Ordinal Encoding

Answer: A

Question 3

You have a Pandas DataFrame that contains missing values. Which of the following methods will replace all NaNs with zeros?

Options :

A : df.fillna(value=0)

B : df.replace(to_replace=np.nan, value=0)

C : df['column_name'] = 0

D : df.dropna(subset=['column_name'])

Answer: A

Question 4

You are developing a web application with Flask and need to collect user-generated data through web forms. What is the most appropriate way to securely collect this data in Python?

Options :

A : Use Python-s input() function to collect data from users.

B : Use Flask-s request.form and sanitize the inputs before storing them.

C : Use JavaScript to collect the form data and send it to Python using cookies.

D : Directly insert form data into a SQL database without modification.

Answer: B

Question 5

You are given a DataFrame df with a column 'Date' of type string in the format 'YYYY-MM-DD'. You want to filter the rows where the year is 2020. Which of the following code snippets is the most efficient way to do so?

Options :

A : df[pd.to_datetime(df['Date']).dt.year == 2020]

B : df[df['Date'].str.contains('2020')]

C : df[df['Date'].str.slice(0, 4) == '2020']

D : df[df['Date'].apply(lambda x: x.split('-')[0]) == '2020']

Answer: C