Test of just four(4) numbers

#1
Hi

I have just four numbers and would like to know if there is a stats test that will tell me if one of them does not belong.
Specifically, I'm looking at the fourth one (below) and want to prove that it is significantly different from the other three.

715
812
677
326

Is this even doable?

Thanks
 

Dason

Ambassador to the humans
#2
What does this data represent. If it's possible to do what you want you would need to make a fair number of assumptions so without more info it's impossible to say.
 
#3
These are estimates of the total cross-sectional area of wood in a small woodlot according to four different sampling methods. I want to prove the low number is the outlier.
 

Dason

Ambassador to the humans
#4
Did you have any reason to believe before seeing the data that that particular sample method was different or was it only after seeing the data that you decided that?