Intrusion detection is one of the basic applications in wireless ad-hoc networks like Wireless Sensor Network (WSN). For Intrusion detection, a number of sensors are deployed in the area to be monitored. There are different types of deployment strategies. In this paper, the authors study two different deployment approaches. If all sensors are deployed uniformly and randomly, they call it as Poisson distribution. In the Gaussian distribution all sensors are deployed around a predefined deployment point. Parameters such as node density, sensing range and Intrusion distance plays important role in Intrusion detection.