CodeHS Data-Driven Decision Making 3

Question 1

Which data cleaning step addresses the problem of the same customer being listed as 'John Smith' and 'JOHN SMITH' in a dataset?

Accepted Answer

Standardizing formats

Answer

Standardizing formats (e.g., converting all text to the same case) ensures consistent representation of the same entity.

Question 2

A bar chart showing app downloads per country is most useful for:

Accepted Answer

Comparing values across categories

Answer

Bar charts excel at comparing discrete categories against a common quantitative axis.

Question 3

If a dataset has values 4, 8, 8, 10, 15, the MODE is:

Accepted Answer

8

Answer

The mode is the value that appears most frequently; 8 appears twice while all other values appear once.

Question 4

A/B testing is BEST described as:

Accepted Answer

Comparing two versions of something to see which performs better

Answer

A/B testing exposes two groups to different versions (A and B) and measures which produces the desired outcome.

Question 5

Which Python library is most commonly used for data manipulation and analysis using DataFrames?

Accepted Answer

Pandas

Answer

Pandas provides the DataFrame structure and tools for loading, cleaning, and transforming tabular data.

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