Hi everyone, I'm Mrs. Horan.

Welcome to today's lesson! It's great to see that you've come along today to work like scientists with me, so let's get stuck straight in.

Today's lesson is part of the unit on human development.

The lesson is called Representing Data about Human Height, and we're going to be looking at ways to visually represent some data so that we can clearly see any patterns.

The outcome for our lesson today is to use averages to create a line graph to show growth rates in humans.

This lesson builds on what you already know about human development, and how human height changes over time.

And it's part of our big learning question, "How do living things grow and reproduce?" These are the keywords that we're going to be focusing on today.

Data, average, line graph and plot.

Some of these words might be new to you and some of them are probably already quite familiar.

We're going to look at each one in detail when we come to it in the lesson, so we'll have a really good understanding of them all by the time we finish.

Here are some of explanations of the keywords.

We don't need to look at these closely now because each one will be explained as we come to it during the lesson.

They're here so you can come back to them at any point in the lesson if you need to check anything or if you need a reminder of what one of the words means.

Our lesson today comes in two parts.

Let's get started with the first part, finding averages.

"Sam has been finding out about human height by measuring people and recording data in a table." Data is information collected during an investigation.

It might be numbers, symbols, pictures, or text.

Sam's data is in the form of numbers and you can see it all in the table here.

She's definitely been very busy.

It looks like she's measured 15 children of different heights and that has given us a lot of numbers to think about.

She says, "There's a lot of data to think about here.

I'm finding it tricky to find any patterns." I think I agree with her on that one.

"How could she make her data easier to analyse?" When scientists have a lot of data to analyse, sometimes they calculate an average to make it easier to find patterns.

You can see we have another keyword in that sentence.

Average.

Let's find out a bit more about averages.

So if Sam finds out the average height for each age, she will only have one number for each age to consider, and it'll be easier for her to find patterns.

You can find an average of a set of numbers by adding them all together and dividing by the amount of numbers in the set.

Let's have a go now with some of Sam's data to help us get our heads around it.

Sam works out the average height for two-year-olds by adding her measurements together and dividing by the number of people.

Here are the heights of the two-year-olds Sam measured.

84 centimetres, 88 centimetres, and 83 centimetres.

So first, she adds those three together to find the total.

84 plus 88 plus 83 equals 255.

Do you remember what we need to do next? Now we need to divide the total by the number of heights we added together.

Sam says, "I've measured the height of three two-year-olds, so I'll divide the total by three." So 255 divided by three makes 85 centimetres.

Sam now knows the average height of the two-year-olds I measured is 85 centimetres.

So now instead of three numbers to think about, we just have one.

85 centimetres.

Can you see how it's quite close to the individual measurements she had? Having just one number, the average, for each age group to think about, will make it much easier for her to find patterns in her results.

Let's have a quick check for understanding because we're dealing with some tricky stuff today.

Why might scientists calculate an average? Do you think it's A, to make large data sets easier to analyse? B, to find a total for all of their data together? Or C, to work out the smallest and largest data points in the set? Which do you think it is? So the correct answer for that one was A.

Scientists might calculate an average to make large data sets easier to analyse.

Now let's give this a go ourselves.

Use Jacob's data to calculate the average height of the one-year-olds he measured.

Remember, to find an average, we add together all of our amounts and divide by the number of amounts we had.

Jacob measured three babies and you can see their heights there.

74 centimetres, 72 centimetres and 79 centimetres.

Pause the video here to have a go at calculating the average height for these one-year-olds.

How did you do? Don't worry if you found that one tricky.

It's often hard to get used to new types of calculating until we become more familiar with them.

So first, we needed to add together the heights that we had.

74 add 72 add 79 equals 225.

Then we have three babies, so we need to divide by three.

225 divided by three is 75.

This means the average heights of the babies Jacob measured is 75 centimetres.

And don't worry if you weren't quite right with that one.

We're going to have plenty of practise with finding averages today, so you can become more confident with it.

"Lucas measured four children who were two years old." You can see his data there with the heights of the Baby A, Baby B, Baby C, and Baby D.

When he calculates his average, what will he have to do differently this time? Pause the video here to have a think about this one.

So Lucas measured four children, so he needs to divide his total by four.

Let's find out what the average height of the babies he measured was.

First, we add together all of the heights, 71 centimetres plus 78 centimetres plus 75 centimetres plus 72 centimetres equals 296 centimetres.

You might be thinking that's a lot of addition to do in your head, but don't worry, it's completely fine to write this down as a column addition to help you find the total, or any other recording method you find useful.

It might even be a good idea to use a calculator for finding some of these totals and averages.

Then we need to divide your total by four, because you have four measurements.

296 divided by four is 74 centimetres.

Again, when you're working these out yourself, feel free to do any written method that helps you, or maybe use a calculator.

Great, so now we've done our calculating.

Lucas knows that the average height of the two-year-olds he measured is 74 centimetres.

Now it's your turn to give this a try again.

Jun's data is in the table there.

What is the average height of the two-year-olds he measured? Remember, the steps are to add together all of the heights, then divide by the number of children that were measured.

Also, remember, you can do any written method that will help you to do these calculations.

Don't feel like you need to work out everything in your head.

Pause the video now to have a go at finding the average.

Welcome back.

Let's see how we did.

First we had to add together all of those heights to find the total.

80, add 87, add 88, add 81 altogether makes 336.

Then we had to divide that total by four because we had four pieces of data.

336 divided by four equals 84.

So the average height of the two-year-olds Jun measured is 84 centimetres.

How did you do with that? If you didn't get it right, have a look back to your calculations to see where you went wrong.

Then you can avoid doing it again next time.

Maybe you forgot to divide your total by the number of children we measured.

Or maybe you made a mistake when you were adding things up or dividing them.

Whatever it was, really focus on getting that bit right next time.

Let's have another try at finding an average.

"What is the average height of the three-year-olds measured by Alex?" I want you to see if you can remember the steps to find an average this time.

So I'm not going to remind you of the method.

See what you can do.

Pause the video now and have a try, and come back when you've calculated the average.

Here we go then.

Let's see what the average is.

Alex only measured two children.

So we only need to add together two numbers this time.

94 centimetres and 95 centimetres together makes 189 centimetres.

Then because we had two heights, we need to divide by two.

189 divided by two is 94.

5, or 94 and a half.

Now Alex knows that the average height of the three-year-old he measured is 94.

5 centimetres.

Well done for keeping going with those.

This is some tricky stuff.

Now you're going to get a chance to have a lot more practise at finding averages in our first practise task of the lesson.

Using Andeep's data on the next slide, or your own that you have gathered during an investigation, if you have it, find the average height for each age.

Here is Andeep's data.

So remember, you can either use your own data or Andeep's, or a combination of both.

If you have some data from a previous inquiry you carried out, but not quite enough to fill the table.

Pause the video here to have a go at finding the average heights for the children at each different age.

Welcome back.

Do you feel like you're getting better at finding averages now you've had lots of practise? Hopefully the things that were catching you out early on aren't causing you any problems anymore.

Here are the averages for Andeep's data.

I'll read through them now, but if you've used your own data, then your averages will be different.

So for two years old, the average height was 85.

75 centimetres.

At four years old, it was 99.

5 centimetres.

Six years old was 113.

5 centimetres.

Eight years old was 125 centimetres.

And 10 years old was 136.

25 centimetres.

I wonder, if you did use your own data, are there any similarities with Andeep's data? It'll be interesting to see how much his results have in common with yours.

Now, for part two of this task, we have something a bit different.

"Andeep and Lucas went to different classes to measure children.

They are comparing their results.

Andeep says, 'Your averages are different to mine, but I know my calculations are correct.

Yours must be wrong.

' Lucas says, 'My calculations are definitely correct too.

'" Can you explain why Andeep and Lucas have ended up with different averages? Pause the video here to organise your thoughts and write down your explanation.

Let's see why they had different answers then.

"All humans are different and so develop and grow at different rates.

Andeep and Lucas measured different children, so their averages will be a little different to each other.

Neither of them is incorrect." Now you don't need to have exactly the same words as me to be correct.

Just the same idea about different children being measured, resulting in different averages.

Time for the second part of our lesson now, line graphs.

Scientists use different types of graphs and charts to make data clear so they can easily see patterns.

Line graphs are often used to show how things change over time.

You can see a line graph in the picture there.

This one shows how the temperature of something changes over time.

We're going to use one to show how human heights changes over time.

Line graphs have two axes.

Axes is a bit of a strange word.

Can you see it there on the end of the sentence? It's a plural of axis, so we say one axis, two axes.

It's spelled the same way as axes that you would use to chop wood, so don't let that catch you out.

The X-axis along the bottom shows the time.

The X-axis on the line graph on screen has been labelled, so you can see where it is.

In our graphs about changes as humans age, this axis will show how many years old the humans are.

The Y-axis, which points upwards, shows what we have measured.

Can you see the Y-axis labelled in the picture there? In our graph, this will show the height of each person.

That can be tricky sometimes to remember which axis is which.

So here's a trick I use.

I remember the phrase "X is across, Y to the sky." Because the letter X is a cross shape, and it also goes across the bottom of the graph.

The Y-axis goes upwards, so "Y to the sky" makes sense.

And it's nice and easy to remember because it rhymes.

So if you get stuck remembering which axis is which, remember, "X is across and Y to the sky." Let's see how we're doing so far with a couple of quick questions.

First, what is the name of this type of graph? The one you can see in the picture there.

Is it A, a data graph? B, a bar chart? C, a line graph? Or D, a pie chart? Well done.

This one is a line graph.

We can tell because the data points have been joined by a line.

Second question.

On this graph, what is shown on the Y-axis? Take a look at the graph on the slide.

If you're having trouble remembering which axis is which, see if you can remember that little rhyme I told you.

So do we think the Y-axis shows A, the age of the children? B, the height of the children? Or C, the number of children that were measured? On this graph, the height of the children is shown on the Y-axis.

Remember, "Y to the sky." Andeep has drawn a line graph and needs to plot his data.

The average height of a two-year-old was 85.

75 centimetres.

First he looks for age two on the X-axis.

There it is in the green box.

Then he needs to move up to 85.

75 centimetres on the Y-axis and plot his data points.

Now as you can see, not every single number is shown on the Y-axis.

Just multiples of 10.

So we'll have to use our knowledge of numbers to work out whereabouts 85.

75 would fall, between 80 and 90.

Well, I know that 85 is halfway between 80 and 90, so 85.

75 is going to be just slightly above the halfway mark between 80 and 90.

And there's his data point.

Now he's plotting the data point for the average four-year-old, which was 99.

5 centimetres.

What does he need to do? Can you remember the steps we took to plot the last data point? First, he looks at age four on the X-axis.

Then he needs to move up to 99.

5 centimetres on the Y-axis and plot his data points.

99.

5 isn't marked on the Y-axis, but we know that it's almost 100, so we know that it's gonna be very close to the 100 mark.

When all of his data has been plotted on the graph, Andeep draws a line between the points to show the changes to human growth rate over time.

This gives us a line that shows really clearly how human height is changing over time.

Let's do one more quick check for understanding before you take on a practise task.

Where should Laura plot this data point? "The average height of the five-year-olds I measured was 110 centimetres." Do you think she should plot that at the point marked by A, B or C? Great, the point should be plotted at B, because it lines up with five on the X-axis, for five years old, and 110 on the Y-axis for 110 centimetres.

Let's have a real go at creating a line graph then.

"Use Laura's data, or your own, to create a line graph showing the average height of different aged children." So you might have some data that you have from an investigation into human height that you carried out yourself that you can use.

That will be great.

Pause the video here to go and complete your line graph.

If you don't have data from an investigation of your own, no problem.

Laura has some data on the next slide, that we can make a great line graph with that too.

Let's take a look at her data.

Here are Laura's averages from the children she measured for you to use if you need to.

Pause the video now and go and complete your line graph, and I'll see you again when you're done.

Welcome back! How did you find creating the line graph? Which parts did you find the trickiest? Were there any parts you found easy? Here is a graph that has been made with Laura's data.

Yours won't be exactly the same if you used your own data, but we know that humans do get taller over time until they reach the end of puberty, so your line should definitely be going upwards like hers is.

We've come to the end of today's lesson.

So let's take a look at that key learning from today.

We can calculate averages to help us analyse and find patterns in large data sets.

Data can be plotted on a line graph to make it easier to analyse and identify patterns.

Human height data can be plotted on a line graph to show growth rate over time.

Thank you for coming to join me today to learn all about representing data on a line graph.

You've done really well with your careful graph drawing and plotting skills.

I'll see you again next time.