What type of example is this: "If it is cold outside, then the boy will wear his blue jacket"?

The answer to this is a hypothesis. The statement is hypothesizing that because it is cold outside, the boy is probably going to wear his blue jacket. If it is an assumption, it will be worded differently. It will be, It is cold outside, therefore, the boy is going to wear his blue jacket.

Creating a hypothesis is considered to be important in the world of science. It will give people a chance to make a scientific and calculated guess on what may possibly occur based on the clues that are observed. Obviously, if it is not cold outside, the boy would have no reason to wear his blue jacket.

There may also be other things that the boy will do instead to protect himself from the potential weather that he will experience when he goes outside.