The batsman has a 1/3 chance of being not out, if the 'Not Out' or 'No Ball' is signalled. As in real cricket a 'No Ball' entitles the batsman to an additional strike (roll) and an extra run.
The probability of a batsman remaining not out is 1/3 if 'Not Out' or 'No Ball' occurs. In actual cricket, a 'No Ball' provides an additional delivery for the batsman to hit and earn more runs.