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Read line plots

A line plot is a graph that displays data using a number line. To create a line plot, ​first create a number line that includes all the values in the data set. Next, place an X (or dot) above each data value on the number line. If a value occurs more than once in a data set, place ​an Xs​ over that number for each time it occurs.

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Video transcript

- [Voiceover] Let's say we're having a birthday party and these are the kids at the birthday party. And all the kids, they have a bunch of different ages, and what we are curious about is how many kids of each age do we have? Well, to help think about that, we can draw what is called a line plot. And I've always viewed the term line plot a bit confusing because in my brain you use a lot more dots than you use lines, but let's look at what a line plot is. So what I will do is I will draw, I guess this involves a line right over here, I'll draw a line down here, and then I'll create buckets for each of the ages. So let's see, I have students here from age three all the way to age seven, so I could say age three, age four, age five, age six, and age seven. I don't have to go to two, or I don't have to go to eight. There aren't any kids in those ages. Although, I could if I want. And then I look at, well, how many kids do I have of each age? Well, I have one person attending the party, Diya, she's age three. So I would put, I might put an X here, or I could put a dot here. Different line plots would put different things here. But that shows me that I have, this partier (chuckles) is age three right over here. Now I have Imran, age five. So that's someone right over here who'd be at age five. You could think of this dot, this represents Imran, who's age five. Then you have Surya, who's also age five. He's also age five, so that means we have a second person at the party who is age five. So under age five, we now have two people. This is Imran and this is Surya. Then you have Jasper, who is six. So that's one person who is age six. Then you also have Vikram, who is age six. Whoops, let me do that in that same color. We also have Vikram, who is age six. So let's put him in the age six bucket. Then we have Luke, who is seven. Luke, who is seven. So that would be a dot right over there. And then finally I have Anya, who's also age six, who is also age six. So just like that, I was able to take all of the data that I have in this table, and I'm able to put it on this line plot. And the reason why this line plot is useful is it helps us look at, well, how many of each age do we have? It might be a little bit more confusing to just look at the table here because when you look at the line plot, it's very clear. Hey look, there's no one here who is age four. And look, we have the most people who are age six. And if we asked ourselves a question, if you didn't even have this. Actually, let me just even take it away. If we didn't even have that there, if we didn't have the table and we just had the line plot, and if someone said hey look, you know, these are ages right over here. This has our ages in years old, and each dot represents a student who's at the party. So based on this line plot, how many people are more than five years old? Well, you could look at this and you could say, okay, more than five years old. That would be six years old or seven years old. It's not showing anyone who's eight, nine, 10, 11, and on, and on, and on, and on. So let's look at all the dots. Let's look at all the dots here that are more than five years old. There are three six-year-olds and there's one seven-year-old. So there are one, two, three, four people who are old than five years old. You could go the other way around. You could say how many people are less than five years old? Well then you could say, okay, less than five years old would be either three years old or four years old. And when you look at those dots, you see there's only one dot. Only one person attending the party is less than five years old. Hopefully, you found that interesting.