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

Forward chaining respects the temporal order of observations by always training on past data and validating on future data, preventing data leakage.

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

A high VIF indicates multicollinearity, meaning the predictor can be largely explained by a linear combination of other predictors in the model.

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

The medallion architecture progressively refines data through distinct layers, making it easier to trace lineage, debug issues, and serve analytics-ready datasets.

Question 4

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

Accepted Answer

Failing to reject a false null hypothesis

Answer

A Type II error occurs when the test fails to detect a real effect, meaning the null hypothesis is not rejected even though it is actually false.

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

Isolation Forest efficiently isolates anomalies by randomly partitioning features, and it works well in high-dimensional spaces without assuming a specific data distribution.

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Data Science FREE Data Science Analysis Question and Answers 3