In today's lecture, I want to talk about an example of subjective probabilities.

In my experience, whenever I introduce the concept of subjective probabilities,

students early on feel a little bit insecure about the idea.

What does it mean subjective probabilities?

How do I develop it?

Can I just pick any numbers for subjective probabilities?

Of course, we can't.

The subjective probability cannot be a 120% or

minus 5%, that would violate the exhumes of probability.

Now, let's look at an example where I would like you to develop

your own subjective probability.

Here's a description of a woman by the name of Linda.

She's 31 years old, single, outspoken, very smart, majored in philosophy.

When she was a student, she was deeply concerned with discrimination,

social justice.

She participated in antinuclear demonstrations.

Now I'm going to give you eight options that describe Linda and

I now would like you to think about what do you think is most likely,

second most likely, lowest probability?

Of course, based on this description, your idea of Linda that you have in

your head may be very different than the idea I have of Linda after reading this.

And so now based on this and your experience, you've got feeling.

You need to develop some subjective probability.

So, what do you think?

Do you think that she is now a teacher in an elementary school?

Or does she work in a bookstore and take yoga classes,

active in the feminist movement?

Is she a psychiatric social worker?

And so on and so on.

When I give this question in class for my students to develop subjective

probabilities, I ask them to give me numbers one through eight.

Most likely a one, least likely an eight.

In this format, I can't quite do this.

So here now we do a little in-class, in-lecture quiz.

I'm now going to offer you a couple solutions and pick the one,

the ranking that's closest to your subjective probability.

It may not be exactly your subjective probability, but

pick the one that you think is closest to your feelings.