In "Data Science Methodology", there are too many grammatical errors and answer errors in the reviews and exam for me to type out.

Before a class is published online, it should have at least passed a basic spell and grammar check. It looks unprofessional.

My suggestion is:

Use a spellchecker before you upload it online. Also, at least one person should go through the reviews and exams to check if everything "looks" okay.

I wanted this course to be supplemental material for my students. But the way it is now, I cannot suggest "Data Science Methodology" to them.