Lesson video

Hello, I'm Mr. Tazzyman.

Today we're gonna be learning about statistics 'cause this unit is all about them.

Statistics we see in lots of different places, so it's a really important unit because it will help us to understand the world around us.

Okay, let's get started.

Here's the outcome for today's lesson then.

By the end, we want you to be able to say, "I can construct line graphs representing two variables." Here are the key words.

Line graph, variable, x-axis and y-axis.

I'm gonna say them and I want you to repeat them back to me.

I'll say my turn, say the word, and then I'll say your turn, and you can repeat it back.

My turn, line graph.

Your turn.

My Turn, variable.

Your turn.

My turn, x-axis.

Your turn.

My turn, y-axis.

Your turn.

Okay.

Here's what each of those keywords means.

A line graph is a graph where the points are connected by lines.

It shows how something changes in value, usually over time.

A variable is something that changes and can also be measured.

The x-axis is the horizontal line on a graph which goes through zero.

The y-axis is the vertical line on a graph which goes through zero.

This is the outline for the lesson then.

We're gonna start by plotting and joining points.

Then we're gonna look at plotting more than one line.

Sofia, Izzy and Jacob are gonna join us today.

They'll be giving us some hints and tips and discussing some of the maths prompts along the way.

Izzy, Jacob, and Sofia are talking about line graphs.

We've got here a line graph showing temperature change.

"A line graph can show how something changes, often over time." "Here is an example of a line graph.

I took the temperature every hour." "The line graph shows the temperature change in between 8:00 AM and 7:00 PM.

The y-axis does not start at zero, but instead starts at minus 10 degrees Celsius." "We can even make readings between the points." "I didn't take a reading at 9:30 AM, but I can estimate what it was." He draws a vertical line between 9:00 AM and 10:00 AM, halfway between, in fact, which is 9:30 AM.

Where does that meet the purple line? Well, you can draw a horizontal line to double check.

"I'd estimate the temperature at 9:30 AM to be seven degrees Celsius." "A measurement can be made at any point on the line, not just those plotted." Here's another line graph.

"A line graph shows how something changes usually over time." "The x-axis shows the day of the week, so the graph shows time changing." It's funny that isn't it we don't always think about days of the week as time changing, but they are units of time as well of course, "The y-axis shows the number of star jumps Jacob did Each day over a week." "We've plotted the number of star jumps Jacob did each day." "Now we can join up the points to create a line graph." "Hold on.

That doesn't work.

Does the line in between the points carry meaning?" Hmm.

"What does this mean here? Did you do 40 star jumps here too?" "Oh, I see what you mean.

We can't use a line graph for this." "I think we'd better make a bar chart to show your star jumps instead, Jacob," Izzy creates a line graph showing her height changing.

Line graph showing Izzy's height from birth to 11 years old.

"This line graph includes divisions on the x-axis and the y-axis.

The variable for the x-axis is time and the divisions show each year." "Height is the variable on the y-axis and divisions show each 10 centimetres.

The y-axis does not start at zero, but instead starts at 40 centimetres.

When Izzy was born, she was 50 centimetres tall, although she couldn't stand up yet." "When Izzy turned one year old, she was 74 centimetres tall.

We can add a horizontal line at 75 centimetres.

74 centimetres is just underneath this line." "On her second birthday, Izzy was 85 centimetres tall." "When I turned three years old, I was 94 centimetres tall." "On her fourth birthday, Izzy was 100 centimetres tall." "When she was five, she was 107 centimetres tall.

I can add a horizontal line at 105 centimetres.

107 centimetres is slightly nearer this line than it is 110 centimetres." Great reasoning, Sofia.

"At six years old, I was 115 centimetres tall." "When Izzy turned seven years old, she was 121 centimetres" "On her eighth birthday, Izzy was 128 centimetres tall." "When I turned nine years old, I was 133 centimetres tall." Good use of estimation then again plotting the point.

"We don't have Izzy's height when she was 10 years old." "This year, on her 11th birthday, Izzy was 144 centimetres tall." The point are joined together to create a line graph.

"I'm going to draw lines connecting one point to the next." "We can now try and estimate Izzy's height on her 10th birthday." "Let's look at the vertical line for Izzy, aged 10 years." "The line graph gives a height between 130 and 140 centimetres." "It's definitely closer to 140 centimetres.

Our estimate Izzy's height was 138 centimetres." Okay, time to check your understanding.

Sofia creates a line graph showing her height changing.

"I think you've made a mistake, Sofia." "Can you help me find the mistake?" So have a look closely.

Where's the mistake? Pause the video and see if you can find it.

Welcome back.

Did you manage to find the mistake? "Your height suddenly decreases here, Sofia.

It looks like you've been shrinking." "Oh no, I've plotted it incorrectly.

I was 128 centimetres tall, aged nine, not 118 centimetres." "The numbers on line graphs can decrease of course, but I don't think it should have happened here." Okay, it's time for your first practise task then.

Create a line graph showing Jacob's height changing.

"Start by plotting all of the points on the line graph using the table." "Be careful.

My height is not given for every year." "Once that's done, join up all of the points." Number two, use your line graph to estimate Jacob's height when he was four years old and 10 years old.

So the line graph there that's blank is for you to fill in with the information from the table previously.

And for this question, you need to do some height estimation for the ages.

Pause the video here and give that graph construction a go.

Good luck.

Welcome back.

Here are the answers.

You can see most of the points have been plotted there.

We've got a couple more to put in.

"117 centimetres is slightly nearer 115 centimetres than it is 120 centimetres.

146 centimetres is just above 145 centimetres." "Once you've plotted them all, join up the points." Okay, if you need to compare your graph with the graph on screen, take the time now to do so.

Let's look at number two then.

At four years old, first of all, "when Jacob turned four years old, his height was approximately 108 centimetres.

When Jacob turned 10 years old, his height was approximately 152 centimetres." Let's move on to the second part, the lesson, plotting more than one line on a graph.

A line graph can include more than one line.

Here's a line graph showing children's journeys to school.

We're creating a line graph which includes our journeys to school.

"We needed to be at school by 9:00 AM but we didn't set off at the same time." Let's start with the journey that Izzy made this morning.

"Izzy lives 1,300 metres away from school." "Izzy didn't leave home until 8:20 AM and walked quite slowly." "Izzy arrived at the pelican crossing and waited for the lights to change." "After a few minutes, the lights changed." "I kept walking and arrived at school at 8:45 AM" "She stood and chatted to some friends until it was time to go into class." "We can join the points together to show Izzy's journey." Jacob uses the line graph to show his journey to school.

"Jacob lives 1,950 metres away from school." "I left at 8:15 AM and headed towards school.

I stopped at Alex's house at 8:25 AM." "Jacob waited for Alex, then they both left Alex's house at 8:30 AM." "They arrived at the crossing at 8:40 AM." "The lights were so slow to change.

We crossed the road at 8:45 AM." "They arrived at school at 8:50 AM and waited to go into class." "We can now join the points together." Okay, let's check your understanding of what we've looked at so far then.

Sofia uses the line graph to show her journey to school.

Do you think Sofia has plotted her journey correctly? Pause the video here and have a think.

welcome back.

Well, Jacob says, "I think you've made a mistake, Sofia, Here you're moving away from school." "I did make a mistake, but not with the line graph," says Sofia.

"I'd forgotten my PE kit and had to go back home for it." "Oh, that's why you are moving away from school." "It looks like you had to rush to get to school." "I got there just in time and at least I now have my kit." Izzy asked a question about the line graph.

"How much further away from school was Jacob than me at 8:30 AM?" "At 8:30 AM, I was 1,400 metres away from school and Izzy was 600 metres away." And you can see he's worked that out by looking up from 8:30 AM on the x-axis to see where the points are plotted.

1,400 metres subtract 600 metres is equal to 800 metres.

"Jacob was 800 metres further away from school than Izzy at 8:30 AM." Jacob asked a question about the line graph.

"What was the earliest that Sofia and I were the same distance from school?" "This is the first time that Jacob and I were the same distance away." "The time is between 8:20 AM and 8:25 AM." The time is slightly nearer 8:20 AM, so 8:22 AM would be a good estimate.

"I still hadn't left home yet." Let's check your understanding then.

Sofia asks a question about the line graph.

"How many metres did I travel all together?" Pause the video here and have a think about that.

Welcome back.

"Sofia leaves home and walks about 400 metres towards school.

She then walks 400 metres back towards home.

400 metres multiplied by two is equal to 800 metres.

She then walks 1,600 metres towards school again.

We need to add 800 metres and 1,600 metres together." Well, 16 plus eight is equal to 24, Izzy's realised that she can use her understanding of some simple calculations to help her with the overall calculation.

1,600 plus 800 is equal to 2,400.

"Sofia walked 2,400 metres altogether." "Wow, that's nearly two and a half kilometres." Okay, it's time for your final practise task then.

You've got to create a line graph showing three children's journeys to school.

"Start by plotting all of the points using the clues given.

Use a different colour each time to join the points together." Here are the clues then.

Aisha lives 950 metres away from school.

She leaves home at 8:35 AM and walks steadily.

By 8:45 AM, she is 500 metres away from school.

She stops to stroke a cat for five minutes, then walks steadily again, arriving at school at 8:55 AM.

"Check you've plotted correctly before joining the points." B, Andeep lives 1,300 metres away from school.

He leaves home at 8:15 AM and walks steadily.

By 8:25 AM, he is 800 metres away from school.

He notices an interesting cloud and stops, watching it for five minutes.

He starts walking again.

Arriving at school at 8:45 AM "Make sure you join the points in the correct order." That's Jacob's tip.

Here's C.

Sam lives 1,850 metres away from school.

Sam leaves home at 8:10 AM and walks steadily.

By 8:25 AM, Sam is 1,200 metres away from school.

Sam has forgotten to bring the homework and rushes back home, arriving there at 8:30 AM.

Sam spends 10 minutes looking for the homework, then starts running to school, arriving there at 9:00 AM.

"Sam's journey is quite complicated, so double check all of your points." says Sofia.

For number two, you need to complete these problems using the line graph you've just constructed.

A, estimate how far from school Andeep was at 8:35 AM.

B, what time was Sam one kilometre away from school? C, how far did Sam travel altogether? And D, how much further away from school was Aisha than Andeep at 8:40 AM? Pause the video here and give those questions a go.

Good luck.

I'll be back soon with some feedback.

Welcome back.

"This is what the line graph should look like.

Sam returned home on the journey." Now pause the video here so you can compare your line graph with the one that's on screen.

Let's look at the answers for number two then.

For A, estimating how far from school Andeep was at 8:35 AM.

"This is where Andeep was at 8:35 AM." There.

"He was closer to 500 metres away than 600 metres away from school." At 8:35 AM, Andeep was approximately 525 metres away from school.

Pause the video here so you can compare your estimates with people around you.

Here's the answer to B then.

What time was Sam one kilometre away from school? "One kilometre is equal to 1,000 metres.

Sam was one kilometre away from school just before 8:50 AM" so your answer may have read, at 8:49 AM, Sam was one kilometre away from school.

Here's the answer for C then, how far did Sam travel altogether? "Between 8:10 and 8:25, Sam travelled 650 metres towards school.

Between 8:25 and eight 30, Sam travelled 650 metres back towards the house.

650 plus 650 is equal to 1,300.

Between 8:40 and 9:00, Sam travelled 1,850 metres towards school." 1,300 plus 1,850 is equal to 3,150.

Sam travelled 3,150 metres altogether.

D, how much further away from school was Aisha then Andeep at 8:40 AM.

"This is where Andeep was at 8:40 AM, approximately 280 metres away from school.

This is where Aisha was at 8:40 AM, approximately 720 metres away from school." 720 metres subtract 280 metres is equal to 440 metres.

At 8:40 AM, Aisha was approximately 440 metres further from school than Andeep.

Your answer should be somewhere between 400 metres and 500 metres.

Okay, that brings us to the end of the lesson.

Here's a summary of our learning.

A line graph is a way of representing the relationship between two variables.

One variable is represented by the x-axis and the other by the y-axis.

Points are plotted like coordinates with a value on the x-axis and a value on the y-axis.

My name is Mr. Tazzyman.

I enjoyed today's lesson.

I hope you did as well.

Maybe I'll see you again soon.

Bye for now.