Medium DA0-002 practice questions

An analyst is finalizing a quarterly PDF report that will be distributed company-wide, including to several employees who use screen readers. The report contains multiple charts summarizing sales performance. To comply with the organization's accessibility policy, what should the analyst do to make the visualizations accessible to these employees?

A retail analyst receives a flat file containing individual point-of-sale transactions, with one row per item sold including store ID, transaction timestamp, and sale amount. The finance team has requested a report showing total revenue per store per day. Which transformation should the analyst apply to prepare the data for this report?

An analyst is preparing a line chart showing monthly customer churn for a quarterly board meeting. Churn was stable until March, when a pricing change caused a sharp spike, then it declined after a retention campaign launched in May. The board has limited time and needs to quickly grasp what drove the changes. What is the most effective way to present this chart so the story is clear at a glance?

A retail analyst ran a promotional pricing experiment exclusively at three flagship stores located in affluent urban downtowns. The promotion increased average basket size by 18%, a statistically significant result. Leadership wants to roll the promotion out to all 400 stores nationwide, including rural and suburban locations, and expects the same 18% lift. What is the MOST important validity concern the analyst should raise?

A data analyst at a fitness center reviews a histogram of member visit frequency per month. The histogram shows two distinct peaks — one cluster around 3 visits and another around 20 visits — with relatively few members visiting between 8 and 14 times. What does this pattern most likely indicate, and what should the analyst do?

A sales operations analyst must build a compact dashboard widget for each regional manager. Each widget needs to show the region's current quarterly revenue, its target for the quarter, and qualitative performance bands (poor, satisfactory, good) so managers can instantly gauge whether they are on track. Space is limited because up to a dozen regions must fit on a single screen. Which visualization type best meets all these requirements?

An analyst is preparing a bar chart of quarterly revenue for a board presentation. To make the slide more visually appealing, a colleague suggests adding 3D depth effects, a decorative background image, and drop shadows behind each bar. What is the primary concern with implementing these suggestions?

A data analyst publishes a shared operations dashboard that pulls from an overnight batch process. During a morning stand-up, several managers make decisions based on numbers they believe are real-time, but the underlying data is actually 12 hours old. To prevent this confusion in future viewings, what should the analyst add to the dashboard?

A retail analyst wants to determine whether a customer's preferred payment method (cash, credit, mobile wallet) is associated with their membership tier (basic, premium). Both variables are categorical, and the analyst has a contingency table of observed counts. Which statistical test is most appropriate to assess whether an association exists between these two variables?

A data analyst at a software company is asked to consolidate three sources for a customer-satisfaction dashboard: a relational table of support-ticket IDs and timestamps, a folder of MP3 recordings from customer service calls, and a set of JSON files exported from a chatbot API. When documenting the data landscape, how should the analyst classify the MP3 call recordings?

A retail analyst is comparing sales performance across three regional stores that opened in different years and had very different starting revenue levels. Leadership wants to fairly compare how much each store has grown relative to its own opening year, not which store has the highest raw dollar sales. Which analysis technique should the analyst apply to enable this comparison?

A retail analyst wants to determine whether average customer satisfaction scores differ across four different store regions (North, South, East, West). Each region has an independent sample of survey respondents, and the analyst wants to test all four regional means simultaneously in a single test while controlling the overall Type I error rate. Which statistical method is most appropriate?

A retail analyst wants to determine whether the average purchase amount differs between customers who received an email coupon and those who did not. Each group contains about 200 customers, the purchase amounts are roughly normally distributed, and the analyst wants to know if the observed difference in group means is statistically significant. Which statistical method is most appropriate?

A market research analyst reports that the average customer satisfaction score is 7.4 with a 95% confidence interval of 6.1 to 8.7, based on a sample of 40 respondents. The marketing director says the estimate is too imprecise to act on and asks the analyst how to narrow the interval while keeping the 95% confidence level. What is the most appropriate action?

A retail analyst reports that the average monthly customer spend is estimated at $84.50 with a 95% confidence interval of $80.10 to $88.90. A store manager asks what the '95% confidence' actually means for this estimate. Which interpretation should the analyst give?

A retail analyst reports that stores offering free in-store coffee have 30% higher sales than stores without it, concluding that coffee service drives sales. A senior analyst notes that all the coffee-serving stores happen to be located in high-income urban downtown areas, while the non-coffee stores are in low-traffic rural locations. What is the primary threat to the validity of the original conclusion?

A data analyst needs to pull data directly from a company's on-premises Microsoft SQL Server database into a desktop analytics tool for a recurring report. The tool must maintain a live connection so refreshes reflect current data, and IT has asked that no data be exported to intermediate flat files. Which acquisition method best meets these requirements?

An analyst is building a multi-page dashboard for a retail company. Each page was created by a different team member, and stakeholders complain that colors, fonts, number formats, and axis scales change unpredictably from page to page, making the dashboard hard to follow. Which reporting best practice should the analyst apply to resolve this?

An analyst receives three monthly sales exports from different regional systems: one CSV, one tab-delimited TXT, and one Excel workbook. All three contain the same columns in the same order (Date, Region, Product, Amount) but were generated by separate teams. The analyst needs to combine all rows into a single dataset for a company-wide report. Which transformation approach is most appropriate?

A marketing analyst calculates the correlation coefficient between monthly advertising spend and monthly sales revenue across the past two years and gets a value of -0.15. Which conclusion should the analyst report to stakeholders?

A retail analyst calculates the Pearson correlation coefficient between weekly inventory levels and weekly sales revenue across 52 weeks and obtains a value of -0.82. Based on this result, how should the analyst describe the relationship between the two variables?

A retail analyst computes a Pearson correlation coefficient of 0.87 between the number of ice cream sales and the number of drowning incidents recorded over the past year. A manager concludes that selling ice cream causes drowning and proposes limiting ice cream sales to improve safety. How should the analyst best respond to this conclusion?

A retail analyst is examining whether monthly advertising spend and monthly sales revenue tend to move together. She wants a single statistic that describes the direction in which the two variables vary jointly, but she is not yet concerned with standardizing the result to a fixed scale. Which measure should she calculate?

An analyst writes a SQL query to combine a Customers table (500 rows) with an Orders table (2,000 rows), expecting roughly 2,000 result rows. Instead, the query returns 1,000,000 rows and runs extremely slowly. Reviewing the query, the analyst notices there is no ON condition linking the two tables. What most likely happened?

You are finalizing an executive dashboard that uses red and green filled bars to distinguish 'below target' from 'above target' KPIs. During review, a stakeholder notes that several executives have red-green color vision deficiency and cannot reliably tell the categories apart. Which change BEST improves accessibility while preserving the dashboard's meaning?