Question: what is the intersection of the assessed probab

title: Probability
text: where h ( \ displaystyle h ) is a constant depending on precision of observation , and c ( \ displaystyle c ) is a scale factor ensuring that the area under the curve equals 1 . He gave two proofs , the second being essentially the same as John Herschel 's ( 1850 ) . Gauss gave the first proof that seems to have been known in Europe ( the third after Adrain 's ) in 1809 . Further proofs were given by Laplace ( 1810 , 1812 ) , Gauss ( 1823 ) , James Ivory ( 1825 , 1826 ) , Hagen ( 1837 ) , Friedrich Bessel ( 1838 ) , W.F. Donkin ( 1844 , 1856 ) , and Morgan Crofton ( 1870 ) . Other contributors were Ellis ( 1844 ) , De Morgan ( 1864 ) , Glaisher ( 1872 ) , and Giovanni Schiaparelli ( 1875 ) . Peters 's ( 1856 ) formula for r , the probable error of a single observation , is well known .