Objective 2.2 Clean Data Sets CERTIFIED-DATA-SCIENCE-PRACTITIONER Practice Questions (Page 1)

Questions 1–5

1. 1foundation · easy

   Which technique is commonly used to detect corrupted data in a dataset?

   • AFeature engineering
   • BRandom sampling without replacement
   • CData normalization
   • DAnomaly detection
   Reveal Solution Discussion Select an answer first
2. 2expert · hard

   A team is building a model to predict customer satisfaction from survey responses. The survey was conducted online, and the team notices that the responses are overwhelmingly positive. Upon investigation, they find that the survey link was primarily shared on a customer loyalty forum. What is the most likely source of bias in this data?

   • AObserver bias from the data analyst.
   • BMeasurement bias from the survey questions.
   • CSelection bias from the data collection method.
   • DConfirmation bias in the analysis.
   Reveal Solution Discussion Select an answer first
4. 3foundation · easy

   Which visualization is commonly used to detect outliers in a single variable?

   • ABox plot
   • BPie chart
   • CLine chart
   • DBar chart
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5. 4foundation · easy

   What is the difference between removing duplicates and deduplicating data?

   • ADeduplication only applies to text data
   • BRemoving duplicates is automated, deduplication is manual
   • CThey are the same thing
   • DDeduplication preserves unique information from duplicate records
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6. 5expert · hard

   A data analyst is cleaning a dataset containing personal health information. The data governance policy states that all cleaning steps must be logged with the date, the person performing the step, and the rationale. The analyst is about to impute missing values for 'blood_pressure'. What is the most important action to take before performing the imputation?

   • ARemove all rows with missing blood pressure values instead of imputing.
   • BDocument the imputation method and rationale in the data cleaning log.
   • CAsk a colleague to review the imputation plan.
   • DCheck if the data is normally distributed to choose between mean and median imputation.
   Reveal Solution Discussion Select an answer first