DSE Basic 5

Question 1

What is the difference between structured and unstructured data?

Accepted Answer

Structured data fits in predefined schemas; unstructured does not

Answer

Structured data is organized in predefined schemas (like tables), while unstructured data lacks a fixed format (like images or emails).

Question 2

Which sampling method gives every member of the population an equal chance of being selected?

Accepted Answer

Simple random sampling

Answer

Simple random sampling ensures every individual has an equal probability of selection, minimizing selection bias.

Question 3

What is a confusion matrix used for?

Accepted Answer

Evaluating classification model performance

Answer

A confusion matrix shows counts of true positives, false positives, true negatives, and false negatives for a classifier.

Question 4

Which of the following algorithms is used for dimensionality reduction?

Accepted Answer

Principal Component Analysis (PCA)

Answer

PCA projects high-dimensional data onto fewer principal components that capture the most variance.

Question 5

In data science, what is a 'data lake'?

Accepted Answer

A centralized repository storing raw data in any format at scale

Answer

A data lake stores raw, unprocessed data in any format at scale, unlike a data warehouse which stores structured, processed data.

DSE - Data Science Practice Test