A healthcare analyst is preparing a dataset of patient blood pressure readings for a regression model. The dataset has 5% missing values in the 'systolic_bp' column. The missing values are not random—they are more frequent in records from older patients. The analyst must choose a method to handle the missing values. Which approach is most appropriate?

Impute missing values with the overall mean of systolic_bp.

Replace missing values with the median systolic_bp of the entire dataset.

Impute missing values using a model that includes age as a predictor, such as regression imputation.

Delete all rows with missing systolic_bp values to ensure a complete dataset.

A data analyst is exploring a dataset and wants to quickly identify which columns contain missing values. Which technique is most appropriate for this initial exploration?

Sort the dataset by each column in ascending order

Create a heatmap visualization of the data matrix

Generate a summary statistics table for each column

Use a function that returns the number of nulls per column

While exploring a dataset, an analyst notices that some cells in the 'Age' column are blank. What does this indicate about the data?

The data is redundant and should be removed

The data contains missing values

An analyst is checking a customer dataset for duplicate records. Which technique is most effective for identifying exact duplicate rows?

Sorting the data by a single column

Using a function to find duplicated rows based on all columns

Calculating the mean of each column

Creating a scatter plot of two numeric columns

Which statistical method is commonly used to identify outliers in a numeric column?

Calculating the mean and standard deviation

Counting the number of missing values

Sorting the column alphabetically

Calculating the mode of the column

CompTIAData+

Domain 2Objective 2

Perform Data Exploration DA0-001 Practice Questions (Page 4)

Part of the Data acquisition and preparation domain, which accounts for 22% of the DA0-001 exam. CompTIA does not publish an official question count, but from its 90-minute exam (~35–60 total, ~8–13 in this domain), expect 3–4 from this objective — we provide 31 practice questions to prepare you well beyond it. (estimate)

31questions here

7free pages

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Questions 16–20

16expert · hard
A healthcare analyst is preparing a dataset of patient blood pressure readings for a regression model. The dataset has 5% missing values in the 'systolic_bp' column. The missing values are not random—they are more frequent in records from older patients. The analyst must choose a method to handle the missing values. Which approach is most appropriate?
Select an answer first
17foundation · easy
A data analyst is exploring a dataset and wants to quickly identify which columns contain missing values. Which technique is most appropriate for this initial exploration?
Select an answer first
18foundation · easy
While exploring a dataset, an analyst notices that some cells in the 'Age' column are blank. What does this indicate about the data?
Select an answer first
19foundation · easy
An analyst is checking a customer dataset for duplicate records. Which technique is most effective for identifying exact duplicate rows?
Select an answer first
20foundation · easy
Which statistical method is commonly used to identify outliers in a numeric column?
Select an answer first

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