DSE Exploratory Data Analysis Techniques 4

Question 1

Which method is commonly used to detect outliers using the IQR?

Accepted Answer

Flag values below Q1 − 1.5×IQR or above Q3 + 1.5×IQR

Answer

The Tukey fence method flags as outliers any values more than 1.5×IQR below Q1 or above Q3, and this threshold is also used by box plots.

Question 2

In a pair plot (scatter plot matrix), what does the diagonal typically display?

Accepted Answer

A histogram or KDE of each variable's distribution

Answer

The diagonal of a pair plot shows the univariate distribution (histogram or KDE) of each variable since a scatter plot of a variable against itself is uninformative.

Question 3

What is the main advantage of using a KDE (Kernel Density Estimate) over a histogram for EDA?

Accepted Answer

It produces a smooth continuous density curve that is less sensitive to bin width choices

Answer

KDE creates a smooth density estimate that avoids the arbitrary bin-width problem of histograms, giving a clearer view of the distribution shape.

Question 4

You have a dataset with 10 features and want to explore relationships between all pairs. How many scatter plots would a full scatter plot matrix contain?

Accepted Answer

100

Answer

A scatter plot matrix for n variables contains n² cells total, so 10×10 = 100 cells (10 diagonal + 90 off-diagonal scatter plots).

Question 5

Which visualization technique is specifically designed to compare distributions across multiple categorical groups simultaneously?

Accepted Answer

Grouped box plot

Answer

A grouped box plot displays side-by-side box plots for each category, enabling direct comparison of median, spread, and outliers across groups.

DSE - Data Science Practice Test

DSE - Data Science Practice Test

DSE Exploratory Data Analysis Techniques 4