Lesson video

Hi, my name is Mr. Hall, and thank you for joining me for this Oak National Academy lesson, which is called "Comparing Data Visually" and is taken from the unit "Flat-File Databases." I'm delighted you've chosen to join me for this lesson today, so let's get started.

The outcome of today's lesson is that you'll be able to explain that computer programmes can be used to compare data visually.

We've got two keywords in this lesson.

So, the first keyword is "chart," and chart is a way of presenting data graphically.

And our second keyword is "axis." So, axis is a line on a chart that shows what the data means.

So, there's our two keywords, "chart" and "axis." And we have two learning cycles in this lesson.

So, first of all, you're going to identify features of charts and then move on to create charts to answer questions.

So, we can get started now with that first learning cycle, which is to identify features of charts.

First of all, just think for a few seconds, what is a chart? And Sam's got a helpful suggestion here.

So, "A chart is a way of presenting data graphically." And we've got an example of a chart on the left-hand side of the screen there.

So, a chart is a picture, like a graph or a diagram, that helps you understand numbers and information more easily.

And there are three types of chart, which you can see on the slide.

So, on the left, which you saw on the previous slide, there's an example of a bar chart.

And then, in the middle, there's a pie chart.

And then, on the right-hand side, there's a flow chart.

And in this lesson, you're gonna take a look mainly at bar charts and pie charts.

So, first of all, a question, where have you seen charts before? And there are some ideas here from Sofia, Laura, and Jacob.

So, Sofia says, "Weather charts show the temperature for each day of the week, so we know if it's going to be hot or cold." Laura says, "In some sports, charts are used to compare players' scores or how many points each team has scored." And Jacob says, "In maths or science, we use charts to track data or show results." So, there's three nice examples of where you might see charts.

Time for a question.

So, the first question is, what is a chart? Is it A, a way of presenting data graphically; B, a way of presenting information correctly, or C, a way of presenting images? So, what is a chart, A, B, or C? That's right, a chart is a way of presenting data graphically.

So, why do we use charts? And again, we've got some really helpful suggestions.

So, Sam says, "Charts make it easier to display and present data." And Sofia adds, "Charts help you compare information and look at similarities and differences." So, we'll look at some examples of both of those now.

So, one of the keywords I mentioned at the beginning was "axis." So, an axis is a line on a chart that shows what the data means.

So, on this chart, we've got two axes.

So, we've got the y-axis, which goes up and down along the side, and we have the x-axis, which goes along from left to right on the bottom.

So, there's our two axes: the y-axis and the x-axis.

In this chart, the y-axis, so the one that goes up and down, shows the number of legs, and the x-axis shows the type of minibeast.

So, on the y-axis, we've got points for zero, two, four, six, and eight legs.

And on the x-axis, for the type of minibeast, we've got fly, slug, spider, and dragonfly.

So, those are two labelled axes.

So the y-axis is labelled "legs," and the x-axis is labelled "minibeast." What does this chart tell us? Well, the title of the chart is "How many legs do minibeasts have?" so that should give us a little bit of a clue.

We can read information using the chart, and the chart tells us that both the dragonfly and the fly have six legs.

So, if you look at the lines for the fly and the dragonfly, they both extend up to six on the y-axis, so six legs for each of those minibeasts.

But this chart tells us more than that.

It tells us that the spider has more legs than all of the other minibeasts.

So, the spider has eight legs, and the most any of the other minibeasts have is six legs.

It also tells us that two minibeasts have the same number of legs and two have different numbers of legs.

So, we've already identified that the fly and the dragonfly both have six legs, they have the same number of legs, the slug has no legs, and the spider has eight legs.

So, there's a lot we can get from this chart.

So, just to recap, the numbers on the side axis, the y-axis, show how many legs each minibeast has.

So now, you're gonna identify the key features of a chart.

So, where do these labels go? First of all, we've got the x-axis for days of the week, the y-axis for number of students, and the title, which is "How many students attended each day?" And each of those can go in either A, B, or C.

So, you need to decide which label goes in A, which label goes where B is, and which label goes where C is.

Okay, here's the answers.

So, first of all, the A is the number of students, so the y-axis is where the A is.

B is the title of the chart, so "How many students attend each day?" goes where B is.

And C is the x-axis, so that's the days of the week.

And you can see on the y-axis we've got number of students, and we've got the numbers going up the side, so that should give you a clue that that's where that one goes.

And on the x-axis, where we've got days of the week, you can see the days of the week labelled on the chart.

And the only one left is the title, and we can tell the title is the title 'cause it's asking a question, which the chart answers.

So, computer programmes that make charts usually label the charts for you.

But Jacob points out, always check any chart you create carefully to make sure it shows the information the way you want it.

The computer will have a go at doing it for you, but it won't always get it right, so it's important that you check it shows what you want it to.

Here's another chart.

It was created from a database about countries.

So, we've got our y-axis, which is population in millions, and our x-axis, which says "country." What could the title of this chart be? So, Jacob says it could be populations of countries in Europe, and Sofia says it could be how many people live in different countries.

So, either of those titles would work well for this chart.

The title of the chart shows what the chart is about and helps explain why the data is being shown.

So, you can see that both Jacob's and Sofia's suggestions would help with that.

Now, answer some questions about this chart.

What does the x-axis show? What does the y-axis measure? And what question could this chart answer? Okay, let's have a look at the answers.

So, the x-axis measures the area in thousands, so that's the axis across the bottom.

And the y-axis represents countries, which you can see on the y-axis going up and down, you've got Belgium, Greece, Switzerland, and Austria as the labelled countries.

And which question could this chart answer? So, it could be, which country has the largest area? Or you could ask, which country has the smallest area? So, any question along those lines.

So, here's another chart.

This time, we've got a pie chart.

So, question four, what does this chart show? Question five, which language has the fewest speakers? Question six, which has more speakers: Spanish or Swahili and Japanese combined? So, question five, the answer the language which has the fewest speakers is Japanese, with 284 speakers.

And question six, which has more speakers, Spanish or Swahili and Japanese combined? Well, Swahili and Japanese combined have 608 speakers, but Spanish has a total of 709 speakers, so it has more speakers than the other two languages combined.

So, that brings us to our second learning cycle, which is to create charts to answer questions.

Charts help you to solve problems or answer a question.

It's important to choose the right type of chart to help you answer questions.

This will change with different types of questions.

These charts were both made from the countries' database.

They were made to answer a question.

The question they were made to answer is, which country has the largest area? Which chart do you think is more suitable, is it chart one or chart two? So, in this case, the pie chart, the slices are hard to compare, especially if the sizes are similar.

So, you can see that the area for countries like the United States, Brazil, Canada, China are all quite similar.

So, it's difficult to tell which one is the largest of those.

However, if we present it as a bar chart, it's easier to see which country has the tallest bar so you can quickly tell which one has the largest area.

And you can also see that Canada has a slightly larger area than the United States, which again is bigger than Brazil and China.

So, it's much easier to tell this on the bar chart than it is on the pie chart.

Time for a true or false question.

The pie chart was more suitable for the question, "Which country has the largest area?" Is that true or false? Well done, that's false.

Can you tell me why? So, as we've just seen, the bar chart was more suitable.

It's easier to see which country has the tallest bar to tell which one has the largest area.

Laura has a question: "Were there more female or male passengers in first class on the Titanic?" Well, you could create a chart to answer this question, and you are gonna do that now.

So, open the Titanic database and follow the link, which is oak.

link/titanic.

That's oak.

link/titanic.

Once you've opened that link, click on the chart tab to open the chart view.

This is the chart tool for the Titanic database.

There are various menus that let you choose what data to include in your chart, and you can see an example there.

To open the search, click on the magnifying glass.

To search for passengers who had first-class tickets, firstly, select "Class" in the first box, then keep the equals sign in the second box, and then select first in the value box.

So, that's "Class" in the first box, equals sign in the second box, and "1st" in the value box.

So, that's what your search will look like, "Class = 1st." And then you need to choose the type of chart here.

So, there are bar charts, pie charts, and other types of charts which you can choose, and there they are, highlighted in that box.

For this one, select the bar chart, and that's the horizontal bar chart option, which is the one on the right-hand side of the five charts.

So, select that one.

Then, in the x-axis box, select "Gender." Select "legend" to make sure your chart's data is labelled, so tick the legend box.

And now we can answer Laura's question, which was, "Were there more female or male passengers in first class on the Titanic?" So, if we look at the graph, this chart makes it easy to answer the question, and we can tell there were more male passengers in first class on the Titanic.

If you want to remove the search filter from your data, click on the red cross to the right of your search boxes.

It will clear the search filter that you made before.

So, there's the red X that you click on.

And Sam points out this is helpful when creating a new chart or working on a new question 'cause you want to get rid completely of your previous search criteria and start a new one.

So always remember, if you want to remove your search filter, use the red cross.

Okay, time to fill in the blanks.

So, we've got a sentence here, which I'll read out, and there are four words which you can include in the blanks.

So, we've got "x-axis," "chart," "data," and "y-axis." And now I'll read out the sentence.

So, a "blank" is a way to show "blank" so it's easier to read and understand.

Charts often have an "blank" and a "blank" to show different parts of the information.

The labels on each axis help explain what the "blank" is about.

Now, fill in the missing parts with the words below.

Okay, well done.

So, a chart is a way to show data so it's easier to read and understand.

Charts often have an x-axis and a y-axis to show different parts of the information.

The labels on each axis help explain what the data is about.

Now, open the Titanic database again, so it's oak.

link/titanic, that's oak.

link/titanic, and use the chart tool to create charts to answer the following questions.

So, first of all, one, were there more female or male passengers on board the Titanic? And in answering that question, you need to give the answer, what chart type you used, what was on the x-axis, and what search you used, if you used one at all.

Okay, let's have a look at the answers.

So first of all, were there more female or male passengers on board the Titanic? So, the answer is there were more male passengers.

The chart type, you could have used either a pie or column or bar chart for that one.

The x-axis should be for gender, so male or female in this case.

And the search, you didn't need to do a search for this particular chart.

So, the next one, in which city did the fewest people board the Titanic? Remember to remove the search filter if you don't need it.

So, we've got answer, the chart type, x-axis again, and the search if needed.

So the question once more, in which city did the fewest people board the Titanic? Let's have a look at the answers.

So, the answer is Belfast.

The chart type that you could use for this one is a pie chart.

And on the x-axis, you needed "boarded" to show where people boarded the Titanic.

Once again, you don't need a search to create this chart.

Question three, in total, how many second-class passengers boarded at Belfast or Queenstown? Remember to remove the search filter if you don't need it.

So once again, I'm looking for the answer, the chart type, what's on the x-axis, and what search you use, if you used one at all.

Okay, let's have a look at this one.

So, the answer is 13.

So, 13 second-class passengers boarded at Belfast or Queenstown.

The chart type you could use for that one was either a bar or a column chart.

On the x-axis, you wanted class.

And this one did need a search.

So the search is "boarded = Belfast" or "boarded = Queenstown," so you've got people that boarded at both Belfast and at Queenstown.

Let's have a look at the summary of this lesson.

So, a chart is a way of presenting data graphically.

Different types of charts can be used to answer different kinds of questions.

A chart helps to compare values, spot patterns, and make data easier to understand.

An axis is a line on a chart that shows what's being measured, such as categories or numbers.

Using a computer to create charts allows data to be organised and updated quickly.

Thank you for choosing to join me for today's Oak National Academy lesson.

I hope you've learned lots about how to compare data visually using charts, and I look forward to seeing you again really soon.