Data Analysis & Reporting Flashcards

When analyzing a dataset with heavy right skew, which transformation is most commonly applied before modeling?

Answer: Log transformation

Log transformation compresses large values and reduces right skew, making distributions more symmetric for modeling.

In a confusion matrix for a binary classifier, which metric is computed as TP / (TP + FP)?

Answer: Precision

Precision measures the proportion of positive predictions that are actually positive: TP / (TP + FP).

A data analyst notices that two features have a Pearson correlation of 0.98. What is the primary concern?

Answer: Multicollinearity

A near-perfect correlation between two predictors indicates multicollinearity, which can destabilize regression coefficient estimates.

Which visualization is most appropriate for displaying the distribution of a continuous variable across multiple categories?

Answer: Violin plot

Violin plots combine a box plot with a kernel density estimate, effectively showing distribution shape across categories.

In time-series analysis, what does the autocorrelation function (ACF) measure?

Answer: Correlation of a series with its own lagged values

ACF measures the correlation between a time series and its own past values at various lag intervals.

When creating a dashboard KPI report, which principle ensures that the most critical metric is immediately visible?

Answer: Above-the-fold placement

Placing the most critical KPI above the fold ensures executives see it without scrolling, following dashboard design best practices.

A feature importance report shows that 'customer_id' ranks as the top predictor. What does this most likely indicate?

Answer: Data leakage from a unique identifier

A unique identifier ranking as top predictor typically signals data leakage, where the ID correlates with the target through improper data joining.