...
what I got from their post is that they basically went to top 50 universities in US which already have some sort of course on blockchain technology and ask their students about cryptocurrencies. of course it didn't mention how those students were chosen, if they were from different departments it would be more accurate than if they asked those participating or have participated in one of these classes.
You got it slightly wrong, as per
coinbase blog:
Key Findings
- 42 percent of the world’s top 50 universities now offer at least one course on crypto or blockchain
- Students from a range of majors are interested in crypto and blockchain courses — and universities are adding courses across a variety of departments
So they went to top 50 unis
and discovered that 42% of them offer blockchain courses. And they did survey across different departments, there's even this bit (quoted from coindesk article) which I find surprising:
While 34 percent of computer science and engineering majors indicated interest in learning about the nascent technology, 47 percent of social science majors are interested in the same, according to the survey.