Sigmoid Function Explained in Less than 5 Minutes

Gabriel Mayers
2 min readJun 22, 2020

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One of the most popular functions is the Sigmoid, a powerful function mainly we’re talking about classification problems.

Basically, the Sigmoid Function returns a value between 1 and 0, this is too powerful for Binary Classification Problems.

But how we can interpret a value returned by a Sigmoid Function?

Intepreting Values Return by a Sigmoid Function

Suppose you trained a Neural Network to classify images of Cats and Dogs, classic problem, where Dog is 1 and Cat is 0. Basically, when your Model returns a values ≥ 0.51 it means the image is of a Dog, and < 0.51 means the image is of a Cat.

The Sigmoid Function Formula is:

Source here

Where:

As you can see, the number 1 as the numerator makes impossible the function returns a value > 1.

When you predict a Dataset using a Sigmoid Function, your result will looks like:

Sigmoid Values

I hope you have managed to understand how Overfitting works!

For now, this is all!

See you next time!

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Gabriel Mayers

Artificial Intelligence Engineer, Science enthusiast, Self-taught and so curious.