logistic regression.

logistic regression.

logistic regression with a

And the term logistic function, that's what give rise to the name logistic progression.

Let's start talking about logistic regression.

light of logistic regression, the Support

like we had for logistic progression.

logistic regression and we're seeing what the mathematical formula is defining the hypothesis for logistic regression.

Z, also called the logistic function, looks like this.

When we plot the logistic function it looks like this

We're going to model a neuron as just a logistic unit.

So, for logistic regression, we had two terms to our objective function.

Now let's think about what we will like the logistic regression to do.

Could we use Naive Bayes, k Nearest Neighbors, Support Vector Machines, Logistic Regression.

logistic regression, I'm going to modify this a little bit, and make the hypothesis

E to the negative Z. This called the sigmoid function or the logistic function.

Logistic Regression is actually a classification algorithm that we apply to settings where the

How about if we were doing a classification problem and say using logistic regression instead.

A plus B. So for logistic regression if we send a very large value of

So, simple logistic regression together with adding in maybe the quadratic or the cubic features

In the next video we'll start working out the details of the logistic regression algorithm.

logistic tracking,, website development, maintenance, customer service, employees, etc, and how does that match revenue streams?

And they were going to have to have those resources, inventory of jerseys, warehouses, logistic systems.

That's the term that a single training example contributes to the overall objective function for logistic regression.

If you want to apply logistic regression to this problem, one thing you could do is apply

And that's called the support vector machine, and compared to both the logistic regression and neural networks, the

line similar to logistic regression but this is going to be the straight line in this posh inning.

Where instead of having basically just one logistic regression output unit, we may instead have K of them.

And finally, the second term here is the regularization term similar to what we had for logistic regression.

Let F of XP, or linear function, and the output of logistic regression is obtained by the following function

And, by the way, the terms sigmoid function and logistic function are basically synonyms and mean the same thing.

We already have linear regression and we have logistic regression, so why do we need, you know, neural networks?

We'll develop an algorithm called logistic regression, which is one of the most popular and most widely used learning algorithms today.

So, in logistic regression we have our familiar form of the hypotheses there and the sigmoid activation function shown on the right.

For such situations there is a model called logistic regression, which uses a slightly more complicated model than linear regression, which goes as follows .

The cost function we use for the neural network is going to be a generalization of the one that we use for logistic regression.

So, it's a pretty close approximation to the cost function used by logistic regression except that it is now made out of two line segments.

The second bit of notational change, we're just designating the most standard convention, when using as the SVM, instead of logistic regression as a following.

It's the same objective function as we always use but we just logistic regression, except that now is define using our m subscript test, test examples.

K equals one through four of basically the logistic regression algorithms cost function but summing that cost function over each of my four output units in turn.

If you look at the cost function of logistic regression, what you find is that each example x, y, contributes a term like this to the overall cost function.

Logistic regression does something similar too of course, but let's see what happens or let's see what the consequences of this are, in the context of the support vector machine.

In that case, the procedure for training and testing say logistic regression is pretty similar first we will do the parameters from the training data, that first 70 of the data.

Finally, one last bit of terminology when we talk about neural networks, sometimes we'll say that this is a neuron an artificial neuron with a sigmoid or a logistic activation function.

My cost function, j of theta is now going to be the following is minus one over m of a sum of a similar term to what we have in logistic regression.