The formal definition of a straddle Options Trading Strategy according to OIC (Option Industry Council) is as follows. "A trading position involving puts and calls on a one to one basis in which the puts and calls have the same strike price, expiration date, and underlying stock."

As you can see in the definition, this options trading strategy involves both puts and calls. So this strategy is suitable for those who cannot decide whether the underlying stock will go up in price or go down.