Data Analytics Interview Questions in Visakhapatnam
36 practice questions with answers for Data Analytics interviews in Visakhapatnam.
Data Analytics jobs in Visakhapatnam
Visakhapatnam (Vizag) has a developing IT market with delivery centres, start-ups and IT parks around Rushikonda. Many local candidates also apply to Hyderabad and remote roles, so a mix of service and product styles is common.
Below are 36 questions that match the mix of service, product and domain employers hiring data analysts in Visakhapatnam.
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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.
02
What is a lambda function in Python and where do analysts use it?
A lambda is a small anonymous function written in one line, for example lambda x: x * 1.18 to add GST. Analysts use lambdas with sorted for custom sort keys, with pandas assign for computed columns, for example assign(margin=lambda d: d.profit / d.sales), and occasionally with apply. For anything longer than one expression or reused in several places, a normal def function is clearer and easier to test.
03
What is the difference between relationships, joins and data blending in Tableau?
Relationships, the default logical layer, connect tables flexibly and Tableau decides join type and level per view, avoiding duplicated measures. Joins physically merge tables into one at a fixed level, which can duplicate rows if grains differ. Blending combines data from separate data sources at the view level using a primary and secondary source, aggregating the secondary first. Prefer relationships, use joins for specific row-level needs, and blending as a last resort.
-- A2:D500 holds Order, Customer, Region, Amount
=FILTER(A2:D500, C2:C500="North", "No orders")
-- two conditions (AND) multiply the tests
=FILTER(A2:D500, (C2:C500="North")*(D2:D500>10000), "No orders")
-- OR conditions add the tests
=FILTER(A2:D500, (C2:C500="North")+(C2:C500="East"))
A story is a sequence of sheets or dashboards, called story points, that walk an audience through an analysis step by step, like slides. Each point can keep its own filters and selections and has a caption explaining the insight. It is useful for presenting findings such as why churn rose, moving from the headline number to segments and recommendations. For everyday monitoring, a regular dashboard is better than a story.
07
Tell me about a time you had to prioritise several dashboard requests at once.
Situation: three managers asked for new dashboards in the same week. Task: I could not finish all of them on time. Action: I asked each about the decision the dashboard would support and its deadline, estimated effort, and shared a proposed order with my manager. I gave one requester a quick interim extract. Result: the most urgent dashboard, for a pricing review, shipped first, and nobody was left without any data.
08
Write an Excel formula to put invoices into ageing buckets (0-30, 31-60, 61-90, 90+ days).
-- C2 = invoice date, TODAY() = as-of date
=LET(age, TODAY()-C2,
IFS(age<=30, "0-30",
age<=60, "31-60",
age<=90, "61-90",
TRUE, "90+"))
-- then a PivotTable with bucket in rows and SUM of amount gives the ageing report
09
What is the medallion architecture (bronze, silver, gold)?
Medallion architecture organises a lakehouse into three layers. Bronze holds raw data exactly as ingested, for audit and reprocessing. Silver holds cleaned, deduplicated, typed and joined data. Gold holds business-ready tables such as star schemas and aggregates used by dashboards. Each layer is built from the previous one by repeatable jobs, so if a cleaning rule changes you can rebuild silver and gold from bronze.
You assume no effect (null), collect evidence and decide whether the data is surprising enough to reject that assumption at a chosen significance level.
12
Write a UTM-tagged URL for a paid Instagram campaign promoting a summer sale, and give two naming rules.
https://www.example.com/sale?utm_source=instagram&utm_medium=paid_social&utm_campaign=summer_sale_2026&utm_content=reel_video_a
-- Rule 1: always lower case with underscores; 'Instagram' and 'instagram' become separate rows
-- Rule 2: keep a shared UTM sheet with allowed source and medium values so every team tags the same way
Sampling bias occurs when the sample does not represent the population, so conclusions do not generalise. Common types: selection bias, such as surveying only app users about website issues; survivorship bias, studying only customers who stayed; non-response bias, when unhappy customers skip surveys; and convenience sampling, using whoever is easiest to reach. Random sampling, stratification and weighting help reduce it.
14
How do you let users choose Top N customers with a parameter in Tableau?
Create an integer parameter Top N with a range of 5 to 50 and show its control. Drag Customer to the Filters shelf, choose the Top tab, select By field, and set it to top Top N by SUM(Sales). Alternatively create a set based on the parameter so you can show Top N versus Others in one chart. If the Top N must respect a category filter, add that category filter to context.
15
A stakeholder wants 20 more visuals added to an already crowded dashboard page. How do you respond?
I would ask which decisions each new visual supports and how often they will look at it. Usually a few are essential and the rest are nice to have. I would propose keeping the main page focused on core KPIs and moving detail into drill-through pages, tooltips or a separate analysis tab. Showing a quick mock-up of both versions helps them see that the cleaner page answers questions faster.
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.
18
What is method chaining in pandas and why is it useful?
Method chaining writes a sequence of transformations as one expression, each step returning a new DataFrame, for example df.query('sales > 0').assign(margin=lambda x: x.profit / x.sales).groupby('region').agg(total=('sales', 'sum')). It avoids many temporary variables, reads top to bottom like a recipe, and reduces SettingWithCopy issues. Wrap the chain in brackets with one step per line, and use pipe for custom functions.
A junk dimension combines several low-cardinality flags and indicators, such as payment type, is_gift, is_express and order channel, into one small dimension table. Each row is a unique combination of those values, and the fact table stores a single key to it. This keeps the fact table narrow and avoids many tiny dimensions or loose flag columns. It works best when the combinations are limited, typically a few hundred rows.
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.
22
Write SQL to calculate monthly customer churn rate.
WITH active AS (
SELECT DISTINCT customer_id,
DATE_TRUNC('month', order_date) AS month
FROM orders
)
SELECT a.month,
COUNT(*) AS active_customers,
COUNT(*) - COUNT(n.customer_id) AS churned_next_month,
ROUND(100.0 * (COUNT(*) - COUNT(n.customer_id)) / COUNT(*), 1) AS churn_pct
FROM active a
LEFT JOIN active n
ON n.customer_id = a.customer_id
AND n.month = a.month + INTERVAL '1 month'
GROUP BY a.month
ORDER BY a.month;
23
What is the difference between a table and a normal range?
=XLOOKUP(1, (A2:A500=G2) * (B2:B500=H2), C2:C500, "Not found")
-- A = product, B = city, C = price
-- G2 and H2 hold the product and city to find
-- each condition returns TRUE/FALSE; multiplying gives 1 only where both match
ROW_NUMBER gives a unique sequence. RANK gives ties the same rank and skips the next (1, 1, 3). DENSE_RANK gives ties the same rank without gaps (1, 1, 2).
26
Write a Tableau calculated field that keeps only sales from the last 30 days.
// Calculated field: Last 30 Days Flag
DATEDIFF('day', [Order Date], TODAY()) <= 29
AND [Order Date] <= TODAY()
// Put this field on Filters and keep True.
// For a sales measure instead of a filter:
// IF DATEDIFF('day', [Order Date], TODAY()) <= 29 THEN [Sales] END
27
Tell me about a time an experiment result went against what the team expected.
Situation: the team was sure a shorter signup form would raise registrations. Task: I owned the test analysis. Action: registrations rose 6%, but I checked the guardrail and found seven-day activation fell, because we had removed a question that personalised onboarding. I shared both results with the segment breakdown. Result: we kept the short form but moved the question to the first screen after signup, which recovered activation.
28
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.
WITH touches AS (
SELECT t.user_id, t.channel, t.touch_ts,
ROW_NUMBER() OVER (PARTITION BY t.user_id ORDER BY t.touch_ts) AS first_rank,
ROW_NUMBER() OVER (PARTITION BY t.user_id ORDER BY t.touch_ts DESC) AS last_rank
FROM marketing_touches t
JOIN conversions c
ON c.user_id = t.user_id
AND t.touch_ts <= c.converted_ts
)
SELECT user_id,
MAX(CASE WHEN first_rank = 1 THEN channel END) AS first_touch,
MAX(CASE WHEN last_rank = 1 THEN channel END) AS last_touch
FROM touches
GROUP BY user_id;
32
What is bidirectional cross-filtering in Power BI and when is it risky?
Normally filters flow from the one side to the many side, for example from Product to Sales. Bidirectional filtering lets filters also flow back, so a Sales filter can limit Product. It helps in some many-to-many or bridge-table cases. The risks are ambiguous filter paths, unexpected results and slower performance. Prefer single direction and use CROSSFILTER inside a specific measure when you need both directions only there.
33
Your pandas script shows SettingWithCopyWarning and a new column does not update. What is happening and how do you fix it?
It warns that you may be modifying a temporary copy of a slice, so the change might not reach the original DataFrame, for example df[df.sales > 0]['flag'] = 1. Avoid it by using a single loc call, df.loc[df.sales > 0, 'flag'] = 1, or by calling .copy() when you intentionally create a new subset. Newer pandas versions with copy-on-write make behaviour more predictable, but clear loc assignments remain best practice.
34
What is the difference between frequentist and Bayesian A/B testing?
Frequentist testing asks how surprising the data would be if there were no difference, and gives p-values and confidence intervals with a fixed sample size. Bayesian testing combines a prior with the data to give a probability that treatment beats control and the expected loss of choosing it. Bayesian results are easier for business users to read, but still depend on priors and still need sensible stopping rules.
35
What is a date table in Power BI and why should you mark it as one?
A date table has one row per day with no gaps, covering the full range of your data, plus columns like year, month, quarter and week. Marking it as a date table tells Power BI to use it for time intelligence functions such as TOTALYTD and SAMEPERIODLASTYEAR. Without it, those functions can give wrong results and auto date tables bloat the model. Relate it to every fact table's date column.
Which companies hire Data Analytics professionals in Visakhapatnam?
Companies with large offices in Visakhapatnam include many IT services and product firms. Use their company pages below to practise employer-specific sets.
Are Data Analytics interviews in Visakhapatnam different from other cities?
The questions depend more on the company than the city. Visakhapatnam's mix of employers decides the style: Many local candidates also apply to Hyderabad and remote roles, so a mix of service and product styles is common
How do I find Data Analytics jobs in Visakhapatnam?
Shortlist companies with Visakhapatnam offices, keep your CV focused on Data Analytics projects, apply on company career pages and job portals with the Visakhapatnam filter, and practise the questions on this page before each interview.