Data Science FREE Data Science Analysis Question and Answers 3

Question 1

Which cross-validation strategy is most appropriate for time series data?

Accepted Answer

Time-based forward chaining (walk-forward validation)

Answer

Standard k-fold cross-validation

Answer

Leave-one-out cross-validation

Answer

Stratified k-fold cross-validation

Question 2

What does a high variance inflation factor (VIF) for a predictor variable indicate in multiple regression?

Accepted Answer

The predictor is highly correlated with other predictors in the model

Answer

The predictor has a nonlinear relationship with the response

Answer

The predictor contributes significantly to the model's accuracy

Answer

The predictor has too many missing values

Question 3

When building a data pipeline, what is the primary advantage of using a medallion architecture (bronze, silver, gold layers)?

Accepted Answer

It separates raw ingestion from cleaned and aggregated data, improving data quality and traceability

Answer

It eliminates the need for data validation

Answer

It reduces storage costs by compressing data at each layer

Answer

It automatically handles schema changes in source systems

Question 4

In hypothesis testing, what does a Type II error represent?

Accepted Answer

Failing to reject a false null hypothesis

Answer

Rejecting a true null hypothesis

Answer

Accepting the alternative hypothesis correctly

Answer

Having an insufficient sample size

Question 5

Which technique is best suited for identifying anomalies in a high-dimensional dataset where normal data forms irregular clusters?

Accepted Answer

Isolation Forest

Answer

Z-score thresholding

Answer

Simple moving average

Answer

Chi-squared test

Question 6

What is the purpose of applying a log transformation to a heavily right-skewed feature before modeling?

Accepted Answer

To compress the range of extreme values and make the distribution more symmetric

Answer

To remove all outliers from the dataset

Answer

To convert categorical data into numerical format

Answer

To normalize the feature to a 0-1 range