Data Analysis and Visualization: Key Concepts and Tools

What is data?

Tabular, computer-readable files composed of rows (records) and columns (fields).

What does the DIKW hierarchy stand for?

Data, Information, Knowledge, Wisdom.

Name three common data file formats.

CSV, XLSX, TXT.

What is raw data?

Unaggregated individual records.

What is summarized data?

Aggregated totals or averages.

What is the difference between primary and secondary data?

Primary data is collected by you; secondary data is collected by others.

What is metadata?

Information describing variables, units, and sources.

What is a 'data state of mind'?

A mindset to spot where data exists.

What are three reasons agencies collect data?

Legal mandates, mission needs, open-government policies.

What is FOIA?

Freedom of Information Act, a path to obtaining data.

What should you specify when requesting offline data?

Dataset name, fields, date range, preferred electronic format.

What is 'data dirt'?

Errors in data, such as duplicates, misspellings, or invalid entries.

What are two common sources of data dirt?

Duplicates and missing values.

What is the purpose of data integrity checks?

To validate datasets for completeness and consistency.

What Excel tools can be used for data integrity checks?

`COUNTIF`, `SUMIF`, `VLOOKUP`, pivot tables.

What is the importance of preserving the original file before cleaning?

To maintain a backup of the unaltered data.

What is the difference between mean and median?

Mean is the average; median is the middle value in a dataset.

Why normalize counts into rates before comparing across regions?

To account for differences in population size.

What are pivot tables used for?

To aggregate and summarize data in Excel.

What are key components of a clear chart?

Labeled axes, units, sources, and context.

What types of charts are best for comparing categories?

Bar charts.

Why should you avoid too many slices in a pie chart?

It can make the chart difficult to read and interpret.

What feature in Excel allows you to add regression lines to scatterplots?

Chart formatting options.

What factors should you consider when choosing a web visualization tool?

Usability, interactivity, and ethical publishing.

What is the first step in using a web visualization platform?

Clean data and export it as CSV.