20+ Junior Data Analyst Interview Questions and Answers for Freshers

Malaria is a mosquito-borne infectious disease caused by parasites. Drug allergy is an adverse reaction to medication. Hypertension is high blood pressure. Diabetes is a metabolic disorder affecting blood sugar levels. Obesity is excessive body weight. GERD is gastroesophageal reflux disease. Gout is a form of arthritis. Hyperlipidemia is high levels of lipids in the blood. Agar agar is a gelatinous substance derived from seaweed. Pigment names refer to various coloring agent...read more

Handling null values involves identifying, analyzing, and deciding on the best method to manage missing data in datasets.

• Identify null values using functions like isnull() in pandas.

• Analyze the impact of null values on your analysis; for example, if a column has 90% nulls, it may be better to drop it.

• Impute missing values using mean, median, or mode for numerical data; for example, replacing null ages with the average age.

• Use forward fill or backward fill methods for time ser...read more

Outliers can skew data analysis; handling them is crucial for accurate insights.

• Identify outliers using statistical methods like Z-scores or IQR.

• Remove outliers if they are errors or irrelevant to the analysis.

• Transform data (e.g., log transformation) to reduce the impact of outliers.

• Use robust statistical methods that are less sensitive to outliers, like median instead of mean.

• Consider the context: an outlier might be significant in certain analyses (e.g., fraud detection).

There are four phases of clinical research: Phase 1, Phase 2, Phase 3, and Phase 4.

• Phase 1: Focuses on safety and dosage in a small group of healthy volunteers.

• Phase 2: Expands to a larger group to see if the treatment is effective.

• Phase 3: Compares the new treatment to standard treatments in a larger group.

• Phase 4: Post-marketing studies to monitor the treatment's long-term effects.

Power BI is a powerful tool for data visualization and business intelligence, enabling insightful decision-making through interactive reports.

• User-friendly interface allows non-technical users to create reports easily.

• Integrates with various data sources like Excel, SQL Server, and cloud services.

• Offers real-time data analytics, helping businesses make timely decisions.

• Provides advanced visualization options, such as charts, maps, and dashboards.

• Facilitates collaboration by s...read more

Candidate key is a unique key that can uniquely identify each record in a table, while a compound key is a key that consists of multiple columns to uniquely identify each record.

• Candidate key is a single column key, while compound key is a combination of multiple columns.

• Candidate key can be a primary key, while compound key cannot be a primary key if it includes non-unique columns.

• Example: In a table of students, student ID can be a candidate key, while a compound key of stu...read more

Stored procedure in SQL is a precompiled collection of SQL statements that can be executed by calling the procedure name.

• Stored procedures help improve performance by reducing network traffic and improving security.

• They can be used to encapsulate complex SQL logic for reuse.

• Parameters can be passed to stored procedures for dynamic execution.

• Stored procedures can also be used for error handling and transaction management.

SQL uses various data types to define the nature of data stored in tables, ensuring proper data handling and storage.

• 1. INTEGER: Used for whole numbers, e.g., 42.

• 2. VARCHAR(n): Variable-length string, e.g., 'Hello World'.

• 3. DATE: Stores date values, e.g., '2023-10-01'.

• 4. FLOAT: Used for floating-point numbers, e.g., 3.14.

• 5. BOOLEAN: Represents true/false values, e.g., TRUE or FALSE.

ICH-GCP guidelines are international standards for designing, conducting, recording, and reporting clinical trials.

• ICH-GCP stands for International Conference on Harmonisation - Good Clinical Practice.

• These guidelines provide a unified standard for the European Union, Japan, and the United States.

• They ensure the protection of the rights, safety, and well-being of trial subjects.

• ICH-GCP guidelines cover aspects such as trial design, conduct, monitoring, auditing, and reporting...read more

Pharmacovigilance involves several phases including signal detection, data collection, data assessment, risk management, and communication.

• Signal detection: Identifying potential safety issues through various sources such as clinical trials, spontaneous reports, and literature reviews.

• Data collection: Gathering information on adverse drug reactions (ADRs) from healthcare professionals, patients, and regulatory authorities.

• Data assessment: Analyzing and evaluating the collecte...read more

Window functions in SQL are used to perform calculations across a set of table rows related to the current row.

• Use the RANK() function to assign a unique rank to each row within a partition of a result set.

• You can use the PARTITION BY clause to divide the result set into partitions to rank separately within each partition.

• Example: SELECT column1, column2, RANK() OVER (PARTITION BY column1 ORDER BY column2) AS rank_column FROM table_name;

One business understanding problem is identifying customer churn reasons in a subscription-based service.

• Analyze customer data to identify patterns or trends leading to churn

• Utilize predictive modeling to forecast potential churn

• Implement targeted retention strategies based on findings

• Monitor and track the effectiveness of retention efforts

Technical skills involve data analysis tools; soft skills enhance teamwork and communication in a data-driven environment.

• Technical Skills: Proficiency in Excel for data manipulation and analysis.

• Technical Skills: Experience with SQL for querying databases and extracting insights.

• Technical Skills: Familiarity with data visualization tools like Tableau or Power BI to present findings effectively.

• Soft Skills: Strong communication skills to explain complex data insights to non-t...read more

Check if a given string is a palindrome in Python.

• Use string slicing to reverse the string and compare it with the original string.

• Remove any spaces and convert all characters to lowercase for accurate comparison.

• Example: 'radar' is a palindrome, 'hello' is not.

A rack and pinion mechanism converts rotational motion into linear motion using a gear system.

• Consists of a circular gear (pinion) and a linear gear (rack).

• When the pinion rotates, it moves the rack linearly.

• Commonly used in steering systems of vehicles.

• Found in machinery for precise linear movement, like CNC machines.

• Used in elevators for lifting mechanisms.

Window function query on lead is used to retrieve the next row in a result set.

• Lead() function is used to access data from the next row in a result set.

• It is commonly used in scenarios where you need to compare data from the current row with data from the next row.

• Example: SELECT column_name, LEAD(column_name, 1) OVER (ORDER BY column_name) AS next_value FROM table_name;

Warehousing is the process of storing and managing goods within a physical location.

• Warehousing involves receiving, storing, and organizing goods in a designated space.

• It includes inventory management, order fulfillment, and distribution.

• Examples of warehouses include Amazon fulfillment centers and distribution hubs for retail stores.

VLOOKup is a function in Excel used to search for a value in a table and return a corresponding value from another column.

• VLOOKup stands for 'Vertical Lookup'

• It is used to search for a value in the first column of a table and return a value in the same row from a specified column

• Syntax: =VLOOKUP(lookup_value, table_array, col_index_num, [range_lookup])

• Example: =VLOOKUP(A2, B2:D10, 3, FALSE) - searches for the value in cell A2 in the first column of the range B2:D10 and return...read more

Form 21 CFR is a document used by the Food and Drug Administration (FDA) to regulate medical devices.

• Form 21 CFR is a regulation set by the FDA for medical devices.

• It outlines requirements for manufacturing, labeling, and marketing medical devices.

• Compliance with Form 21 CFR is necessary for selling medical devices in the US.

Types of brakes in vehicles include disc brakes, drum brakes, and anti-lock brakes.

• Disc brakes use calipers to squeeze brake pads against a rotor to slow down the vehicle.

• Drum brakes use brake shoes to press against the inside of a drum to stop the vehicle.

• Anti-lock brakes prevent wheels from locking up during braking, allowing the driver to maintain steering control.

Oscillation is a repetitive variation, typically in a wave-like pattern.

• Oscillation refers to the repetitive movement or fluctuation around a central point.

• It can be seen in various phenomena such as pendulum swings, sound waves, and electronic signals.

• The frequency, amplitude, and phase are important characteristics of oscillation.

• Oscillation can be described mathematically using trigonometric functions like sine and cosine.

Union combines datasets with similar structures, while Join merges datasets based on related columns.

• Union combines results from two or more SELECT statements with the same number of columns.

• Example: SELECT column1 FROM table1 UNION SELECT column1 FROM table2.

• Join merges rows from two or more tables based on a related column.

• Example: SELECT * FROM table1 JOIN table2 ON table1.id = table2.foreign_id.

• Union removes duplicate records, while Join can include duplicates based on th...read more