In the data table above, were produced by sleep researchers studying the number of dreams people recall when asked to record their dreams for one week, group x consisted of 100 people who observed early bedtimes and group y consisted of 100 people who observed later bedtimes. If a person is chosen at random from those who recall at least one dream, what is the probability that the person belong to group y? All right, so this is a two table probability. So that is what a two table part of it looks like. Whenever you're trying to answer these questions, it is almost like the only thing that really matters with these is understanding when you're trying to come up with a probability what is going to be the numerator and what is going to be a denominator. What are you going to be dividing by and what are you dividing with?

All right. So what do you read, you want to read from here? This is Is the meat of this question. That's where it matters. And they're asking, if a person has chosen at random, from from from from those who recalled at least one dream, you stop right there and what you've just read is your denominator. Okay?

So my denominator is going to be the total number of those who recalled at least one dream. So we will go up, take a look at total number of those who are called at least one dream. So here is people who are called none, we don't want those. Here's the people who called at least 124, and five or more. So the total here are everybody who recalled at least one dream. So everybody here so the total of this.

Alright, so you can add 28 plus 57 plus 11 plus 68. Or you can just add 39 plus 125 cents, that is the total for each call. Awesome. So that is the total for our denominator. which happens to be 164. If you add all those together, you'll get 164.

All right, now let's move on to the second part of this sentence, what is the probability that the person belongs to group y. So in our numerator is going to be the total number of those who at least had one dream from group y. So let's move on up here, right, we still don't want this column because that is the column that people had no dreams, they were called no dreams. And we want to look in GroupWise the total of those who had at least one dream, so this will be this, these guys right here. So you're going to add then 11 plus 68. Okay, and that will give you a total of 79.

And let me put my 79 up here. And that should look most similar to see. Look at that. We found that out all by ourselves. So, again, the really the only thing that matters here is knowing how to read the question and convert it basically into a fraction. What is my pool?

What am I dividing by? And what am i dividing with? What is my numerator