How do I make something happen based on a %?

Let's say I have 60 bunnies on the screen, each colored white.

But then I click a button labeled "May turn a bunny blue". 'May' means could, so there's a chance a bunny could turn blue if I press that button.

How do I say that I want an event to have a 50% chance of occurring?

I'm not sure why all my questions involve bunnies, hopefully I made sense though.

if button is clicked AND random(100) < 50 then turn the bunny blue.

or you could do

if button is clicked AND choose (0,1) = 0 then turn the bunny blue.

Thanks! I assume you're talking about the Compare Two Values event. The first option works perfectly, thank you.

If I have a button, and I want it to goto a layout 4/5 times, and goto another 1/5 times, how would I go about doing that. Thanks.

2 layouts. 1 called "one" & 1 called "two".

Go to (layout) choose("one","one","two","one","one")

Or using #spacedoubt method:

button is clicked

random(100)<80 --> go to layout1

else --> go to layout2

AS yet another alternative, you may check this tutorial that deals with the subject.