Abstract: Wireless sensor network is a collection of sensor, which senses the data and perform the action, according to data. Where as wireless sensor and actor networks (WSANs) contain a group of sensors and actors connected via wireless medium. The sensor node senses the data and then transfers it to the actor. The actor performs the action according to the data. Sensor nodes in wireless sensor and actor network, have some hardware and software restrictions. Due to which, fault may occur in sensor as well as in network. However, some research emphasises on the link fault without considering the fault in sensing the data. Because of this, the node may sense incorrect data and perform the incorrect action. To solve this issue, Five Number Summary method for fault tolerance (FNSMFT) may be used.