Random Actions?

iam making a Life of a peasent style map but its sort of different, iam making it so every 2 minutes their is a chance a giant crab monster appears, what i cant figure out is how to make a chance that it wont happen?, so basicly i need a "Random" action

Depending on how high % chance for the monster to appear you want you'll have to use Math - Random Number between 1 and 100, if you want a 1% chance that is.

Do it like this:
Set ChanceOfCrapAppearing = Math - Random Number between 1 and 100
If ChanceOfCrapAppearing = 1
then Create Unit
else Do Nothing.

This way in 99 out of 100 cases, the monster wont appear. Say you want a 50 % chance of him appearing just use random number between 1 and 2.

thanks milkman that helps alot

There have been some trouble with using random number with low numbers- the results are not always very random... That's why it is suggested you use a higher number like 100 and if you want a 50-50 chance, just do "if randomNumber smaller than or equal to 50 then create crab..."

Of course, using this every 2 minutes, you must be careful: true, if you have, let's say, 25% chance of the crab appearing, that would mean you get, on average, one crab every eight minutes; but that's just the average, with some bad luck you could get 3 crabs in 6 minutes, now if batteling these giant crabs takes longer than that, you could get overrun. Always be careful when using statistics :)