the OP's last sentence suggests a way to test the hypothesis that islands prone to disaster are just as likely to be encountered as islands not prone to disaster. If the hypothesis is true, then island colonization attempts should have failed 83% of the time.

Of course, such a finding would imply the attempts succeeded 17% of the time. A similar conclusion can be made about galaxy colonization - a small percentage of these attempts will be successful - i.e., the galaxy will be colonized.