How to calculate false alarm in n flows in NS2 ?

Description

The ratio of the number of genuine nodes misclassified as attackers from total number of genuine nodes is known as false alarm.

Result:

N = 2
Number of genuine routers in flow1 a = 2
Number of genuine routers in flow2 b = 3
Number of misclassified nodes in flow1 c = 1
Number of misclassified nodes in flow2 d = 2
False alarm = c / a + d / b
= 1 / 2 + 2 / 3
= 7 / 6 * 0.1
= 0.116666667×100
= 11.66