Objective 3.2 Preprocess Data CERTIFIED-DATA-SCIENCE-PRACTITIONER Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   Which imputation method replaces missing values with the most frequently occurring value in a column?

   • AMedian imputation
   • BMode imputation
   • CModel-based imputation
   • DMean imputation
   Reveal Solution Discussion Select an answer first
2. 17foundation · easy

   Which formula represents min-max normalization for a value x?

   • A(x - min) / (max - min)
   • B(x - mean) / standard deviation
   • C(x - median) / interquartile range
   • Dx / sum(x)
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4. 18foundation · easy

   Which factor is most important when deciding between imputation and record removal?

   • AThe data type of the target variable
   • BThe number of features in the dataset
   • CThe order of rows in the dataset
   • DThe extent and pattern of missingness
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5. 19application · medium

   A data analyst receives a dataset with 500,000 rows and 50 columns. They run `df.isnull().sum()` and find that the column 'customer_age' has 200,000 missing values. They also plot the missing values and notice that missingness in 'customer_age' is concentrated in rows where 'subscription_type' is 'premium'. The 'subscription_type' column is complete. What is the most appropriate first step to inform the handling strategy?

   • AImpute 'customer_age' with the median age of all customers.
   • BDelete all rows with missing 'customer_age'.
   • CInvestigate whether the missingness is related to other observed variables.
   • DReplace missing 'customer_age' with the mode age.
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6. 20application · medium

   A data scientist is imputing missing values in a dataset. The column 'education_level' is categorical with values 'High School', 'Bachelor', 'Master', and 'PhD'. The missingness is MCAR. The data scientist wants to choose an imputation method that preserves the distribution of categories. What should the data scientist do?

   • AImpute with the median education level.
   • BImpute with the mean education level.
   • CDelete rows with missing education level.
   • DImpute with the mode education level.
   Reveal Solution Discussion Select an answer first