36 practice questions with answers for Data Analytics interviews in Nagpur.
Data Analytics jobs in Nagpur
Nagpur's MIHAN SEZ hosts IT-services and BFSI delivery centres, giving central India a steady market for data and QA roles. Interviews are usually service-company style, with aptitude, technical and HR rounds.
Below are 36 questions that match the mix of service, product and domain employers hiring data analysts in Nagpur.
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01
Traffic suddenly doubled from one city, with near-zero engagement time and no conversions. What is happening and what do you do?
This is very likely bot or spam traffic, or a misfiring tag. Check the user agents, IP ranges, hostnames, screen resolutions and landing pages for that traffic. If it is bots, exclude it with filters or data segments in analytics and in your reporting layer, and inform the web team so they can block it. Then restate the affected dashboard numbers, because bots inflate sessions and pull down conversion rate.
02
Your A/B test ends with no significant difference. How do you report it?
A flat result is still useful. Report the observed difference with its confidence interval, for example -0.3% to +0.8%, which shows the range of effects still possible. State whether the test had enough power for the planned MDE. If it did, conclude that any effect is probably small and the team can choose based on cost or simplicity. Share learnings so the same idea is not retested blindly.
03
What is the difference between mean and median for reporting salaries?
-- Works in PostgreSQL, Snowflake, SQL Server (with OVER for SQL Server)
SELECT
city,
PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY order_value) AS median_value,
AVG(order_value) AS mean_value
FROM orders
GROUP BY city
ORDER BY median_value DESC;
A calculated column is computed row by row and stored in the model. A measure is computed at query time using the filter context, e.g. Total Sales = SUM(Sales[Amount]). Prefer measures for aggregations.
07
Tell me about a time you found a serious data quality issue.
Situation: while building a returns report I noticed one warehouse had zero returns for three months. Task: confirm whether it was real. Action: I compared with the source system and found its return codes had changed after a software update, so my filter missed them. I informed the data owner, updated the mapping and back-filled the history. Result: the corrected report showed that warehouse had the highest return rate, which led to a packaging review.
08
What is the difference between a t-test and a z-test?
Both compare means. A z-test assumes the population standard deviation is known or the sample is large, so the normal distribution applies. A t-test estimates standard deviation from the sample and uses the t-distribution, which has heavier tails for small samples. In practice analysts mostly use t-tests: one-sample, independent two-sample (Welch's version if variances differ) or paired, for before-after measurements on the same users.
09
What is a transaction and what do the ACID properties mean?
A transaction is a group of SQL statements that succeed or fail together, such as debiting one account and crediting another. ACID: Atomicity means all or nothing; Consistency means rules and constraints stay valid; Isolation means concurrent transactions do not see each other's partial work; Durability means committed data survives crashes. Analysts mostly read data, but knowing ACID explains why reports should read committed data.
A conformed dimension is one dimension table with the same keys, attributes and meanings shared by several fact tables. For example, one date and one product dimension used by sales, returns and inventory facts. Because they conform, you can compare sales and returns by the same product category in one report without mismatched definitions. Conformed dimensions are the main way an enterprise warehouse stays consistent across departments.
11
A measure shows correct values per row in a table visual, but the grand total looks wrong. Why, and how do you fix it?
Totals in DAX are not the sum of visible rows; the measure is recalculated in the total's filter context. A measure like a distinct count, a ratio or an IF condition can give a different result at total level. If the business wants the sum of row values, iterate explicitly, for example SUMX ( VALUES ( Product[Name] ), [My Measure] ). Confirm with stakeholders which total is correct before changing it.
12
How do you merge two DataFrames on different column names?
Situation: I built a Tableau operations dashboard, and the warehouse head said it was too complex to use on the floor. Task: make it useful for them. Action: I watched how supervisors worked, learned they needed three numbers on a tablet every hour, and rebuilt it with large KPI tiles and one drill-down. Result: daily usage went from a handful of users to every shift supervisor within two weeks.
14
Write pandas code to extract month name, weekday and hour from a timestamp column.
A Type I error is a false positive: concluding there is an effect when there is none, for example launching a feature that does not actually lift sales. Its probability is alpha, often 0.05. A Type II error is a false negative: missing a real effect, with probability beta. Power is 1 minus beta. Larger samples reduce Type II errors, and the business cost of each mistake should guide which one you guard against more.
A flat table is quick to start and fine for a small one-off analysis. But at scale it bloats the model because repeated text attributes compress poorly, makes DAX filters and time intelligence harder, and breaks when you add a second fact like targets or returns. I would show them a star schema with one fact and a few dimensions, compare model size and measure speed, and let the results convince them.
Use a star schema, remove unused columns, prefer measures, reduce visuals per page, limit high-cardinality fields and use aggregations or incremental refresh.
SUMIFS sums values meeting several criteria and is fast. SUMPRODUCT multiplies arrays and adds them, handling more complex conditions and weighted totals.
22
How do you make a dashboard accessible, for example for colour-blind users?
Avoid red-green as the only difference; use colour-blind-safe palettes such as blue and orange, and add icons, labels or patterns so meaning never depends on colour alone. Ensure enough contrast between text and background, use readable font sizes, and add alt text to visuals. Keep a logical tab order for keyboard users, and offer a table view of chart data. Accessible dashboards are usually clearer for everyone.
23
Design a dashboard for CXOs — what principles do you follow?
Start from the business questions, show 4–6 top KPIs with trend vs target, allow drill-downs, keep colours consistent, remove clutter, add time/region filters and give one clear insight per visual.
24
Tell me about a time you handled a request for access to sensitive data.
Situation: a regional manager asked for a salary-level export of all employees to plan hiring. Task: help without breaking data policy. Action: I clarified the actual need, which was headcount cost by grade and location, checked with HR on access rules, and built a Power BI view with aggregated costs and row-level security limiting each manager to their region. Result: the manager got what was needed and no individual salaries were exposed.
Situation: our sales reports used five separate Excel extracts and numbers never matched. Task: build one reliable model. Action: I listed the business questions, fixed the grain at invoice line, built conformed date, product and branch dimensions and moved logic into SQL views, then rebuilt the Power BI reports on top. Result: refresh time dropped from 40 to 6 minutes and month-end reconciliation queries fell sharply.
27
Write SQL to find the top 3 products by revenue within each category.
WITH ranked AS (
SELECT category,
product,
SUM(amount) AS revenue,
DENSE_RANK() OVER (
PARTITION BY category
ORDER BY SUM(amount) DESC
) AS rnk
FROM sales
GROUP BY category, product
)
SELECT category, product, revenue
FROM ranked
WHERE rnk <= 3
ORDER BY category, rnk;
I would first agree on definitions: gross or net, including tax or returns, order date or invoice date. Then compare one small slice, such as one month and one region, in both. I check filters on the report and page, relationships that drop unmatched rows, refresh time versus the Excel extract time, and duplicate rows. Once the gap is explained, I document the definition in the report so the question does not repeat.
30
What questions do you ask a stakeholder before building a dashboard?
Who will use it and what decisions will they make with it? Which three to five questions must it answer? What are the KPI definitions, targets and comparison periods? Which data sources are trusted? How often will they look at it, and on what device? Who needs access and are there security restrictions? What does success look like in a month? I summarise the answers in a short brief and get sign-off before building.
31
A report filters WHERE order_date = '2026-03-31' and misses almost all orders from that day. Why?
order_date is probably a DATETIME or TIMESTAMP column, so the filter matches only rows at exactly midnight, 2026-03-31 00:00:00. Use a half-open range instead: WHERE order_date >= '2026-03-31' AND order_date < '2026-04-01'. This keeps the index usable, unlike wrapping the column in CAST or DATE(), and it correctly includes orders at 23:59:59.500. Also check the time zone of the stored timestamps.
32
Which KPIs would you include in an HR attrition dashboard?
Core KPIs: headcount, monthly and annualised attrition rate, voluntary versus involuntary split, and early attrition within the first 90 days or first year. Breakdowns by department, location, manager, tenure band, performance rating and salary band show where it concentrates. Add hiring metrics such as time to fill and offer acceptance rate, and exit reasons from exit interviews. Protect privacy by hiding very small groups.
33
What is the difference between Goal Seek and Solver?
Goal Seek changes one input to hit a target output; Solver optimises with several variables and constraints, for example maximising profit under budget limits.
34
What is the difference between a calculated field and a helper column in Excel?
A calculated field lives inside a PivotTable and works on summarised data; a helper column is a normal column of formulas that feeds the PivotTable or other formulas.
DIVIDE(numerator, denominator, alternate) handles division by zero or blank safely and returns blank or the alternate value you supply, so visuals do not show errors or infinity. The / operator returns an error or infinity in those cases. For example, DIVIDE([Profit], [Sales]) shows blank for a product with no sales. Use / only when you are certain the denominator can never be zero, because it is marginally faster.
Which companies hire Data Analytics professionals in Nagpur?
Companies with large offices in Nagpur include Persistent Systems, GlobalLogic. Use their company pages below to practise employer-specific sets.
Are Data Analytics interviews in Nagpur different from other cities?
The questions depend more on the company than the city. Nagpur's mix of employers decides the style: Interviews are usually service-company style, with aptitude, technical and HR rounds
How do I find Data Analytics jobs in Nagpur?
Shortlist companies with Nagpur offices, keep your CV focused on Data Analytics projects, apply on company career pages and job portals with the Nagpur filter, and practise the questions on this page before each interview.