Answer / Step-by-step explanation:
In this exercise, we know that the agency collected 1,829 bullets which according to the agency, all came from different source.
The number of pair of bullet is :
(1,829) = 1, 829 ! / 2! ( 1,829 - 2 ) = 1, 829 x 1,828 x 1827 ! / 2 x 1 x 1,827
( 2 )
= 6, 108,413,724 / 3654
= 1671,706.
Also, we know that the agency found 658 matches. According to this, the chance of false positive ( that is, the agencies find a match but the bullets are from two different source ) is
P (False positive ) = 658 / 671,706
= 0.000979.
The probability is small to an extent, therefore, we should have confidence in the agency forensic report and evidence
