It would be good to be able to complete the quizzes even if you are not paying for the certificate, this would enable people to understand how much they have taken away from the class.
Executive Summary: Do not spend time on this course if you have minimal common sense and have read at least one article on Data Science.
I finished the 11 week course "Machine Learning - Stanford University - by Andrew Ng" 2 months ago, which was such a great course! It kept me busy for about 20 days (at about 4-6 hours per day) and I learned so much!
This course "A Crash Course in Data Science - Johns Hopkins University" , Part of a 5-course series, the Executive Data Science Specialization, provided just some superficial obvious information, took me only 3 hours to complete and even this time I would could wasted time.
Finally coursera now starts to make courses smaller and smaller and them adding multiple of them up to "Specialization", so that at the end you have to pay much more to get a certain amount of information and course time. With this course they seem to have streched it to a new extreme. The price for the certificate for this superficial short mini course has reached the same price ($ 44) as what I payed for the extensive great Machine Learning course from Stanford University by Andrew Ng !