# Video: Using a Matrix to Represent Data

The given bar chart shows actual and predicted data for several continents about the percent of the population who live in urban areas. Represent this data in a matrix where the rows represent years in order from past to future and the columns represent the continents in alphabetical order.

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### Video Transcript

The given bar chart shows actual and predicted data for several continents about the percent of the population who live in urban areas. Represent this data in a matrix where the rows represent years in order from past to future and the columns represent the continents in alphabetical order.

To first form the matrix, what we’re gonna to need to know is how many rows and how many columns is our matrix going to have. We can see from the question that our rows are gonna represent our years. So if we use this information and go down look at the bar chart, we can see that actually on the bar chart there are three years: 1950, 2007, and 2030. So therefore, we know that they’re gonna be three rows in our matrix.

And now we can take a look at the columns because actually if we look back at the question, we can see that the columns represent the continents. So therefore, if we take a look at our bar chart, we can actually see that our bar chart there are five continents.

So therefore, we can say that our matrix is going to have five columns. So therefore, we can say that the matrix is going to be three by five. So okay, what we can do now is actually set up our matrix. But before we do, I’m gonna be representing our percentages as decimals.

So for instance, we got 51 percent. It’s gonna be 0.51. Or if I had 41 percent, it’d be 0.41, etc. So first of all, I’m gonna start in the first column with Africa. And that’s because it wants the continents to be in alphabetical order.

And the first percentage I’ve written in is 0.15 or 15 percent. And that’s because that’s from 1950, so we want to go from the past to the future. Okay great, so that’s our first element in. So now I’ve completed the rest of the first column, which is Africa. So we got 0.15, 0.37, and 0.51.

So now I’ve moved to our second column. And the second column is actually Asia. So we’ve got 0.17, 0.41, and 0.54, again, moving from the past so 1950 up to the future, 2030.

Then I’ve moved on to our third column. And this one is Europe. So we’ve got 0.51, 0.72, 0.78. And then our next column is actually going to be North America. And it is North America cause remember that we’re moving in alphabetical order. So it’s North America then South America.

So that’s gonna be 0.64, 0.79, 0.87. And then finally, we’re moving on to our last column which is going to be South America, which is 0.42, 0.76, 0.84. Therefore, we have represented the data shown in our bar chart in a matrix, where the rows represent the years in order from past the future and the columns represent the continents in alphabetical order.