[kokx]

The source you mention does not explicitly give a one in 30.000 figure, and it is not something that can be safely concluded from the data in the paper. The authors state that at the time 132,686 people had received their first AZ shot in Norway, of which five had developed thrombosis.

This is definitely not enough data to conclude a 1 in 30,000 figure. And neither does the cited paper conclude this.

[greenwich26]

5 developed the disease 7 or 8 days after the vaccination. Not sure what you're getting at...sampling error? It's a binomial distribution, right? Back of the fag packet maths, we can easily reject 1 in a million, and put a reasonable upper bound below 1 in 100,000.