"likely as not" is a correct and usable phrase in written English.
It is typically used to indicate a probable outcome. For example, "It's likely as not that he'll be late."
If a woman rival uses a six iron for a shot, Babe will likely as not use an eight out of sheer vanity.
"Even though I know that what it would tell me would likely as not be untrue, which is a funny state to be in".
In a newspaper, "the Mideast" will likely as not be euphemistic shorthand for the conflict between Jew and Arab in what used to be called the Holy Land.
As likely as not staffed by a woman, more likely than not staffed alone.
But since 1980, children are as likely as not to earn less than their parents did.
And that, likely as not, is how she would end her days.
Likely as not, the past suggests, the bubble is going to get pricked.
Voters today are as likely as not to approve a state tax increase.
But likely as not, the seller now knows that the item is rare and valuable.
Tell them you're going to Portugal and they are as likely as not stumped.
As likely as not he would be helping himself to a bowl of my breakfast cereal.
