MS-DS Master of Data science Exploratory Data Analysis 2

Question 1

Which statistical measure is MOST resistant to the influence of outliers when describing the center of a distribution?

Accepted Answer

Median

Answer

The median is not affected by extreme values because it depends only on the middle rank, not the magnitude of any values.

Question 2

A violin plot combines which two visualization types?

Accepted Answer

Box plot and kernel density estimate

Answer

A violin plot overlays a kernel density estimate on each side of a box plot, showing both distributional shape and summary statistics.

Question 3

When performing EDA on a dataset with 50 features, which technique best identifies groups of highly correlated predictors?

Accepted Answer

Clustered heatmap of the correlation matrix

Answer

A clustered heatmap reorders features by hierarchical clustering so correlated blocks appear together, making multicollinearity visible at scale.

Question 4

What does a right-skewed (positively skewed) distribution indicate about the relationship between mean and median?

Accepted Answer

Mean is greater than median

Answer

In a right-skewed distribution, the long tail on the right pulls the mean upward beyond the median.

Question 5

In the context of EDA, what is the primary purpose of a quantile-quantile (Q-Q) plot?

Accepted Answer

Assessing whether data follows a theoretical distribution

Answer

A Q-Q plot plots sample quantiles against theoretical quantiles; points falling on the diagonal line indicate the data matches that distribution.

MS-DS Master of Data science Practice Test