50 comptia data+ practice test Practice Questions: Question Bank 2025

A data analyst is asked to explain why a relational database is preferred over a spreadsheet for a customer ordering system that has customers, orders, and order line items. Which concept BEST justifies the database choice?

A dataset contains a "Status" column with values like "open", "Open", "OPEN", and "opn". Downstream reports group these as separate categories. What is the BEST first step to improve data quality?

A team needs to quickly summarize the typical value of "weekly spend" for a customer segment, but the data has several extreme outliers. Which measure is MOST appropriate?

A dashboard shows total sales by month for the last two years. Which visualization is MOST appropriate to show the trend over time?

A retailer wants to identify which products are frequently purchased together to improve cross-sell recommendations. Which data mining technique should the analyst use?

A dataset has many missing values in the "Age" field. The analyst suspects the missingness is not random (e.g., younger users skip the question more often). Which approach is BEST to reduce bias during analysis?

A BI report shows a conversion rate that differs from the same metric in the transactional system. The report uses a join between "Visits" and "Orders" on customer_id only. Which issue MOST likely explains the discrepancy?

An analyst needs to present average delivery time by region. One region has significantly fewer orders than others. What is the BEST way to communicate reliability/uncertainty in the visualization?

A company is building a model to predict customer churn. Churn occurs for only 3% of customers. Accuracy is high, but the model rarely identifies churners. Which metric is MOST appropriate to prioritize during evaluation?

A healthcare organization wants to let analysts use patient data for trend analysis while preventing re-identification. The dataset contains quasi-identifiers such as ZIP code, birth date, and gender. Which control BEST supports this requirement?

A data analyst is asked to quickly show how many orders each customer placed last month in a relational database. Which SQL operation is MOST appropriate?

A dashboard displays a KPI with inconsistent values because analysts are using different definitions for “active customer.” Which governance artifact BEST addresses this issue?

A report needs to compare the distribution of delivery times across multiple shipping carriers. Which visualization is BEST suited to show medians and variability while highlighting outliers?

A retailer has historical purchase data labeled as “churned” or “retained.” The team wants to predict whether a current customer will churn. Which data mining technique should be used?

A dataset contains a column named "revenue" stored as text with values like "$1,200.50" and "1 350,75" from different regions. The analyst needs accurate numeric calculations. What is the BEST first step?

A team is building a curated analytics dataset from multiple source systems. They need to keep the raw, immutable copies of source data for reprocessing and auditing. Which environment component BEST fits this requirement?

A stakeholder complains that a monthly trend line “looks flat,” but the analyst used a y-axis range from 0 to 2,000,000 even though values vary only from 950,000 to 1,050,000. What change BEST improves interpretability without being misleading?

After joining a customer table to an orders table, the analyst notices total revenue is inflated. Investigation shows multiple records per customer exist in the customer table due to duplicates. What is the MOST likely cause of the inflated totals?

A healthcare analytics team wants to share de-identified patient data with a third-party researcher. The researcher still needs to track the same patient across multiple visits, but the third party must not be able to determine the original patient identity. Which technique BEST meets this requirement?

A company uses a model to predict loan default risk. An audit finds the model performs well overall but significantly underestimates risk for one protected group. Which action is MOST appropriate to address this issue while maintaining model governance?

A data analyst needs to combine customer records from a CRM with website session logs. The CRM uses a unique customer_id, but the web logs only contain email addresses. Which approach is BEST to enable a reliable join between the two sources?

A dashboard shows average order value by region. Two regions have very few orders, causing their averages to swing dramatically day to day. Which visualization change is MOST appropriate to communicate the uncertainty?

A data steward is implementing data quality checks on an incoming product catalog feed. Which check BEST validates the "completeness" dimension of data quality?

A team is building a churn prediction model. During evaluation, they find high overall accuracy but very poor performance identifying churners (the minority class). Which metric is MOST appropriate to prioritize for improving identification of churners?

A retail dataset includes a "discount" field. An analyst notices values like "10%", "0.1", and "ten percent" all in the same column. What is the BEST first step before analysis?

A marketing analyst wants to identify common combinations of products purchased together to inform cross-sell recommendations. Which data mining technique is MOST appropriate?

A BI developer is designing a report to compare revenue across 30 product categories with long names. The current vertical bar chart is cluttered and labels overlap. Which change is BEST to improve readability while preserving comparisons?

A data engineer built a pipeline that loads sales transactions nightly. The business reports that some transactions are missing, and investigation shows the pipeline filters rows where "status" = "complete". However, upstream systems sometimes send "Complete", "COMPLETE", or "complete ". What control would BEST prevent this issue long term?

An analyst is asked to estimate the causal impact of a new website checkout flow on conversion rate. Randomized A/B testing was not performed, but there is a similar group of users who did not receive the new flow during the same period. Which approach is MOST appropriate to estimate impact while accounting for time trends?

A company is deploying a semantic layer so multiple teams can query consistent business metrics (e.g., "net revenue") across tools. Which design choice BEST supports consistency and governance?

A data analyst is asked to add clear definitions for each field in a shared dataset so that business users interpret the metrics consistently. Which deliverable BEST meets this requirement?

A team wants to ensure that analysts can reproduce a monthly report exactly, even if the underlying operational data changes later. Which approach is BEST?

A dataset contains a column called customer_id that should always be present for each row. Which data quality check BEST verifies this requirement?

A visualization shows quarterly revenue broken down by region and quarter. Which chart type is MOST appropriate to compare totals while also seeing contributions by region?

A marketing analyst wants to segment customers into groups based on similarity across features such as age, spending, and website visits. No labeled outcomes are available. Which technique should the analyst use?

An analyst builds a model to predict equipment failure, but failures occur in only 1% of records. The model achieves 99% accuracy by predicting 'no failure' for every case. Which metric would BEST highlight that the model is not useful?

A report shows a sudden spike in daily orders. Investigation reveals that a batch job reprocessed the same transaction file twice, resulting in duplicates. Which control would BEST prevent this issue going forward?

A stakeholder wants to compare the distribution of customer satisfaction scores across three product lines and identify outliers. Which visualization is BEST?

An analyst is evaluating the relationship between advertising spend and sales. Both variables are heavily right-skewed with a few extreme values. Which approach is MOST appropriate before computing a correlation intended to reflect the typical relationship?

A company must allow analysts to query customer behavior data while ensuring that personally identifiable information (PII) cannot be reconstructed from shared outputs. Which technique BEST addresses this requirement while preserving analytical utility?

A data analyst notices that a dataset contains multiple fields where missing values are stored as "N/A", "", and "-999" depending on the source system. Which step should the analyst take FIRST to improve data quality for analysis?

A dashboard shows monthly revenue by region. Stakeholders complain that the chart makes it difficult to compare trends over time across regions because lines overlap frequently. Which visualization change would BEST address this issue?

A data team wants to ensure that only approved users can view customer PII in a reporting tool, while allowing most employees to view aggregated metrics. Which control BEST supports this requirement?

A retail company wants to identify products that are frequently purchased together to optimize cross-selling recommendations. Which data mining technique is MOST appropriate?

A dataset of web sessions has 2% fraudulent sessions. A model achieves 98% accuracy by predicting "not fraud" for every session. Which metric would BEST reveal the model’s poor performance on fraud detection?

A data analyst is preparing to join two tables: Orders(order_id, customer_id, order_date) and Customers(customer_id, email, state). The analyst finds that Customers has multiple rows per customer_id due to historical email changes. What is the MOST likely risk if the analyst performs a simple inner join on customer_id without resolving duplicates?

A business report requires a single metric called "Active Customer". Different teams currently calculate it differently (e.g., 30-day activity vs. 90-day activity). Which governance artifact BEST helps standardize this definition across the organization?

A visualization shows the distribution of employee salaries and is heavily right-skewed with a few extremely high values. The mean appears much higher than what most employees earn. Which measure of central tendency should the analyst report to BEST represent a "typical" salary?

A healthcare analytics team must publish de-identified patient data for research. They remove direct identifiers (name, SSN) but retain age, ZIP code, and admission date. A reviewer warns that individuals could still be re-identified by combining quasi-identifiers. Which approach BEST mitigates this risk while preserving analytical usefulness?

A model is trained to predict customer churn. During evaluation, the confusion matrix shows high precision but low recall for the churn class. The business goal is to contact as many likely churners as possible, even if some contacted customers would not have churned. What is the BEST adjustment?