> Yes, it's wrong to assume that you can tell everything about that dog by looking at it - but it's so much more uncomparably wrong to consider that you can tell nothing about friendly or sick dogs based on looking at them!

but nobody in this entire thread was saying that, and my contribution was an additional attempt to further point out why the other sibling responses were missing this

At this point I'm totally content in talking past each other on this topic as I honestly don't know why its not clear that the subset which is undetectable by mere observation is statistically significant.