DA Data Cleaning and Preparation 2

Question 1

What is data parsing in the context of data preparation?

Accepted Answer

Extracting structured information from raw or unstructured text

Answer

Sorting rows in ascending order

Answer

Merging two datasets

Answer

Computing summary statistics

Question 2

Which technique rescales data so the mean is 0 and standard deviation is 1?

Accepted Answer

Standardization (Z-score scaling)

Answer

Min-max normalization

Answer

Log transformation

Answer

Binning

Question 3

What is the purpose of data profiling?

Accepted Answer

Assessing data quality, structure, and content before analysis

Answer

Generating charts for stakeholders

Answer

Training predictive models

Answer

Encrypting sensitive fields

Question 4

What is binning (bucketing) in data preparation?

Accepted Answer

Grouping continuous values into discrete categories or intervals

Answer

Removing rows with missing values

Answer

Encoding binary outcomes

Answer

Splitting strings by delimiter

Question 5

What is a regex (regular expression) commonly used for in data cleaning?

Accepted Answer

Pattern-based text extraction, validation, and replacement

Answer

Joining tables on matching keys

Answer

Computing running totals

Answer

Converting wide data to long format

Question 6

What does 'tidy data' mean as defined by Hadley Wickham?

Accepted Answer

Each variable is a column, each observation is a row, and each type of observational unit is a table

Answer

Data sorted by date

Answer

Data with no missing values

Answer

Data stored in a single flat file