Data Science Analysis 3

Question 1

What is the primary goal of exploratory data analysis (EDA)?

Accepted Answer

To understand patterns, anomalies, and structure before modeling

Answer

EDA uncovers distributions, relationships, and data quality issues that guide later modeling.

Question 2

Which technique is best for visualizing the relationship between two continuous variables?

Accepted Answer

Scatter plot

Answer

A scatter plot maps each pair of values to a point, revealing trends and correlations.

Question 3

A column has 40% missing values. Which is generally the most cautious first step?

Accepted Answer

Investigate why values are missing before imputing or dropping

Answer

Understanding the missingness mechanism prevents biased imputation or unwarranted data loss.

Question 4

Standardizing a feature (z-score) transforms it to have:

Accepted Answer

Mean 0 and standard deviation 1

Answer

Z-score scaling subtracts the mean and divides by the standard deviation, yielding mean 0, SD 1.

Question 5

Min-max normalization rescales values to which range by default?

Accepted Answer

0 to 1

Answer

Min-max scaling maps the minimum to 0 and the maximum to 1.

Data Science Practice Test