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Data MCQ With Answers

40 practice questions · Last updated on Sep 21, 2022

Q&A guide Share:

Data jobs are booming with the industry growing by an average annual rate of 13%. In fact, seasoned data analysts are leading highly rewarding careers right now, with packages going over 20 LPAs.

And this segment is going to help you achieve the same too.

Browse through some of the most important questions asked in Data related job interviews across top companies in India like Amazon, Deloitte, TCS, KPMG, etc.

Data MCQ

1.Which SQL clause filters rows after aggregation?

2.What is the logical order of execution in a SQL query?

3.What happens when a LEFT JOIN has a condition on the right table in the WHERE clause?

4.What is the most common cause of inflated totals after a SQL join?

5.What does COUNT(column) do differently from COUNT(*)?

7.Which window function always produces unique sequential numbers within a partition?

8.Which window functions retrieve values from previous or subsequent rows?

9.Why can a window function not be used directly in a WHERE clause?

10.What does a NULL value represent in SQL?

11.When should the median be preferred over the mean?

12.Why is reporting a central value alone usually insufficient?

13.What does correlation between two variables establish?

14.What is the gold standard for establishing causation?

15.What does a p-value actually represent?

16.Why can a statistically significant result still be commercially meaningless?

17.What happens if you test twenty independent hypotheses at a 0.05 threshold?

18.What is the difference between OLTP and OLAP systems?

19.Why should heavy analytical queries not run against the production transactional database?

20.What distinguishes a data lake from a data warehouse?

21.Why has ELT largely replaced ETL in modern data stacks?

22.What is a fact table in dimensional modelling?

23.What should be done before imputing a missing value?

24.What is the correct approach to outliers?

25.Which SQL pattern finds duplicate records?

26.What is the most common cause of a lookup failing on values that look identical?

27.What is the fastest way to sanity check an analysis before presenting it?

28.Which chart type is appropriate for showing the distribution of a variable?

29.Why should a bar chart's value axis start at zero?

30.What makes a chart title effective?

31.What is the first question to ask when given a vague analysis request?

32.Why should definitions such as active customer be agreed in writing before analysis?

33.What distinguishes a data engineer from a data analyst?

34.What does an analytics engineer typically do?

35.Which practice most improves the reliability of a data pipeline?

36.What is an index in a database primarily used for?

37.What does a Common Table Expression (CTE) provide?

38.What is the difference between UNION and UNION ALL?

39.Why should raw source data be preserved untouched during cleaning?

40.What should you do first when a stakeholder disputes your numbers?

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