What is the URL where the issue is happening

https://roadmap.sh/ai-data-scientist

What browsers are you seeing the problem on?

Chrome

Describe the Bug

Experimental Design Article link leads to a 404 page not found error (https://towardsdatascience.com/step-by-step-for-planning-an-a-b-test-ef3c93143c0b)

Output from browser console (if any)

No response

Participation

• I am willing to submit a pull request for this issue.