Probability is a stereotype in SysML. You can apply it to outgoing edges of decision nodes and object nodes. When Cameo Simulation Toolkit simulates a decision node or an object nodes whose outgoing edges stereotyped with probability, it will use the probability values collected from all outgoing edges to select one outgoing edge that it will go to.
Supported Probability Values for Decision Nodes on Outgoing Edges.
Normally, the summation of the probability values from all outgoing edges should be 1.0 (100%). If this is not the case, Cameo Simulation Toolkit will scale the probability values with the summation.