Resolve "The Three Levels of Data Analysis"

Closes #4699 (closed)

Review app: https://4699-the-three-levels-of-data-analysis-2.about.gitlab-review.app/blog/2019/11/04/three-levels-data-analysis/

Checklist for writer

• Link to issue added, and set to close when this MR is merged
• Add disclaimer copy to the top and bottom of your blog post file: https://about.gitlab.com/handbook/marketing/blog/unfiltered/#disclaimers
• Blog post file formatted correctly, including any accompanying images
• unfiltered category entered in frontmatter
• Review app checked for any formatting issues
• Reviewed by fellow team member
• Assign to someone on your team with maintainer access to merge

/label ~"unfiltered"