Explore foundational concepts in data science with this beginner-friendly set of interview questions. Whether you’re gearing up for interviews or just starting to explore data science, these questions will enhance your understanding of important concepts and techniques in the field.

### Data Science Interview Questions for Beginners – Set 1

Question 1: Which data structure is used to store unique elements in Python?

List

Tuple

Dictionary

Set

**View Answer**

**Answer: Set**

Question 2: Which Python library is commonly used for numerical computing?

NumPy

pandas

TensorFlow

SciPy

**View Answer**

**Answer: NumPy**

Question 3: In a normal distribution, what percentage of data falls within one standard deviation from the mean?

99.7%

95%

50%

68%

**View Answer**

**Answer: 68%**

Question 4: What is the purpose of cross-validation in machine learning?

To evaluate model performance on unseen data

To increase training time

To reduce bias in the model

To overfit the model

**View Answer**

**Answer: To evaluate model performance on unseen data**

Question 5: Which of the following is not a data visualization tool?

Jupyter Notebook

Tableau

matplotlib

Power BI

**View Answer**

**Answer: Jupyter Notebook**

Question 6: What is the formula for calculating correlation coefficient?

Variance(X) * Variance(Y) / Covariance(X,Y)

Covariance(X,Y) / (Variance(X) * Variance(Y))

Standard Deviation(X) * Standard Deviation(Y) / Covariance(X,Y)

Covariance(X,Y) / (Standard Deviation(X) * Standard Deviation(Y))

**View Answer**

**Answer: Covariance(X,Y) / (Standard Deviation(X) * Standard Deviation(Y))**

Question 7: Which of the following is a supervised learning algorithm?

Decision tree

K-means clustering

K-nearest neighbors

Apriori algorithm

**View Answer**

**Answer: Decision tree**

Question 8: What is the purpose of regularization in machine learning?

To increase model complexity

To increase bias and reduce variance

To speed up training time

To reduce overfitting

**View Answer**

**Answer: To reduce overfitting**

Question 9: Which of the following is not a type of data distribution?

Poisson distribution

Binomial distribution

Normal distribution

Sequential distribution

**View Answer**

**Answer: Sequential distribution**

Question 10: Which of the following is not a type of data distribution skewness?

Infinite skewness

Zero skewness

Negative skewness

Positive skewness

**View Answer**

**Answer: Infinite skewness**

Question 11: What is the purpose of a boxplot?

To compare multiple datasets

To display the relationship between two variables

To display the distribution of a dataset

To identify outliers in a dataset

**View Answer**

**Answer: To identify outliers in a dataset**

Question 12: Which of the following is not a step in the CRISP-DM (Cross-Industry Standard Process for Data Mining) framework?

Modeling

Deployment

Data Visualization

Evaluation

**View Answer**

**Answer: Data Visualization**

Question 13: What is the p-value in hypothesis testing?

Probability of rejecting a false null hypothesis

Probability of rejecting a true null hypothesis

Probability of accepting a true null hypothesis

Probability of accepting a false null hypothesis

**View Answer**

**Answer: Probability of accepting a false null hypothesis**

Question 14: Which of the following is not a dimensionality reduction technique?

Singular Value Decomposition

t-Distributed Stochastic Neighbor Embedding (t-SNE)

Linear Regression

Principal Component Analysis (PCA)

**View Answer**

**Answer: Linear Regression**

Question 15: Which of the following is not a type of join in SQL?

Outer join

Parallel join

Cross join

Inner join

**View Answer**

**Answer: Parallel join**

Question 16: What does SQL stand for?

Standard Query Language

Sequential Query Language

Structured Question Language

Structured Query Language

**View Answer**

**Answer: Structured Query Language**

Question 17: Which algorithm is used for outlier detection?

Decision tree

Linear Regression

Isolation Forest

K-means clustering

**View Answer**

**Answer: Isolation Forest**

Question 18: Which of the following is used to detect and handle missing values in a dataset?

Mean imputation

All of the above

Median imputation

Mode imputation

**View Answer**

**Answer: All of the above**

Question 19: Which Python library is commonly used for web scraping?

BeautifulSoup

pandas

NumPy

SciPy

**View Answer**

**Answer: BeautifulSoup**

Question 20: Which of the following is a supervised learning algorithm used for classification?

PCA (Principal Component Analysis)

Decision tree

K-means clustering

t-SNE (t-Distributed Stochastic Neighbor Embedding)

**View Answer**

**Answer: Decision tree**

Question 21: Which of the following is not a type of SQL constraint?

Foreign Key

Primary Key

Secondary Key

Unique

**View Answer**

**Answer: Secondary Key**

Question 22: What is the primary purpose of ETL (Extract, Transform, Load) in data warehousing?

To prepare data for analysis

To store data

To analyze data

To visualize data

**View Answer**

**Answer: To prepare data for analysis**

Question 23: What is the purpose of feature scaling in machine learning?

To reduce the number of features

To increase the dimensionality of the dataset

To introduce noise into the dataset

To standardize the range of independent variables

**View Answer**

**Answer: To standardize the range of independent variables**

Question 24: Which statistical measure is used to measure the central tendency of a dataset?

Variance

Standard Deviation

Correlation

Mean

**View Answer**

**Answer: Mean**

Question 25: Which of the following is used to represent missing or null values in pandas?

NaN

None

NA

All of the above

**View Answer**

**Answer: NaN**