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Data Acquisition and PreparationhardMultiple SelectObjective-mapped

DA0-002 Data Acquisition and Preparation Practice Question

A data analyst is performing EDA on a dataset with numerical features. Which methods are appropriate for identifying outliers? (Select TWO).

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Z-score method

IQR method uses Q1 - 1.5*IQR and Q3 + 1.5*IQR to define outliers. Z-score method uses threshold (e.g., |Z| > 3) to identify outliers.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Mean imputation

    Why it's wrong here

    Imputation is for handling missing values, not outlier detection.

  • Pearson correlation coefficient

    Why it's wrong here

    Correlation measures relationship, not outliers.

  • Z-score method

    Why this is correct

    Points with |Z| > 3 are often considered outliers.

  • Standard deviation alone

    Why it's wrong here

    Standard deviation alone doesn't identify outliers; Z-score uses it.

  • Interquartile range (IQR) method

    Why this is correct

    Outliers are points below Q1 - 1.5*IQR or above Q3 + 1.5*IQR.

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