Data Science Data Cleaning and Preparation 3

Question 1

The interquartile range (IQR) method is commonly used to detect:

Accepted Answer

Outliers

Answer

Values outside 1.5×IQR beyond the quartiles are flagged as outliers.

Question 2

Min-max scaling transforms a feature to which range by default?

Accepted Answer

[0, 1]

Answer

Min-max scaling rescales values to the 0 to 1 range.

Question 3

Z-score standardization produces data with:

Accepted Answer

Mean of 0 and standard deviation of 1

Answer

Standardization centers data to mean 0 and unit standard deviation.

Question 4

Which encoding creates a separate binary column for each category value?

Accepted Answer

One-hot encoding

Answer

One-hot encoding generates one binary indicator column per category.

Question 5

Why scale features before training a k-nearest-neighbors model?

Accepted Answer

Distance calculations are sensitive to feature magnitude

Answer

KNN uses distances, so unscaled large-magnitude features dominate.

Data Science Practice Test