Objective 3.1 Examine Data CERTIFIED-DATA-SCIENCE-PRACTITIONER Practice Questions (Page 1)

Questions 1–5

1. 1expert · medium

   A data scientist has a dataset with 5 numerical features and wants to identify which pairs have the strongest linear relationships. They compute a correlation matrix. The highest absolute Pearson correlation is 0.95 between 'feature_A' and 'feature_B'. What is the most important next step before using both features in a regression model?

   • AIgnore the correlation because it is just a number.
   • BUse a heatmap to confirm the correlation.
   • CRemove both features immediately to avoid overfitting.
   • DInvestigate multicollinearity, as the high correlation suggests the two features may be redundant.
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2. 2foundation · easy

   Which statistical method identifies outliers by measuring how many standard deviations a data point is from the mean?

   • APearson correlation
   • BVariance
   • CZ-score
   • DIQR
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4. 3foundation · easy

   Which outlier detection method uses the interquartile range (IQR) to define boundaries?

   • AIQR method
   • BZ-score
   • CScatter plot
   • DHistogram
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5. 4foundation · easy

   Which of the following is the most important consideration when identifying the target feature for a predictive model?

   • AThe feature that is easiest to collect
   • BThe feature with the most missing values
   • CThe feature with the highest variance
   • DThe feature that directly represents the business outcome to be predicted
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6. 5application · medium

   A data scientist is analyzing the relationship between 'years_of_experience' and 'salary' for a set of employees. A scatter plot shows a clear monotonic increasing trend, but the relationship is curved (exponential), not linear. The Pearson correlation is 0.85, and the Spearman correlation is 0.95. Which correlation coefficient is more appropriate to report?

   • ABoth are equally valid; report either one.
   • BPearson, because it is the most commonly used and the value is still high.
   • CSpearman, because it measures monotonic relationships and is not affected by the curvature.
   • DNeither; use a heatmap instead to show the relationship.
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