Data Science Data Science MCQ 4

Question 1

What is multicollinearity in a regression model?

Accepted Answer

High correlation among predictor variables

Answer

Multicollinearity occurs when independent variables are highly correlated with each other.

Question 2

Which activation function outputs values between 0 and 1 and is often used for binary classification output?

Accepted Answer

Sigmoid

Answer

The sigmoid function squashes inputs into the (0, 1) range, suitable for probabilities.

Question 3

What does the bias-variance tradeoff describe?

Accepted Answer

The balance between underfitting and overfitting error sources

Answer

Lowering bias often raises variance and vice versa, so models must balance both.

Question 4

Which SQL clause is used to filter groups after aggregation?

Accepted Answer

HAVING

Answer

HAVING filters aggregated results, whereas WHERE filters individual rows before grouping.

Question 5

What is the purpose of a train-validation-test split?

Accepted Answer

To tune hyperparameters and get an unbiased final performance estimate

Answer

The validation set tunes hyperparameters while the held-out test set gives an unbiased estimate.

Data Science Practice Test