Scatter graphs and correlation
Plot height against shoe size for a class and a pattern usually appears — scatter graphs reveal relationships that a table of numbers hides.
Part of your national curriculum
- Statistics: Describe simple mathematical relationships between two variables in observational and experimental contexts and illustrate using scatter graphs
Lesson overview
What you'll learn in this lesson
Describe simple mathematical relationships between two variables in observational and experimental contexts and illustrate using scatter graphs
Key learning points
- • Types of correlation
- • Worked example
- • Reading a line of best fit
This lesson at a glance
- 24 minutes
- 16 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 16
Visual introductionPicture this
Scatter graphs and correlation
Plot height against shoe size for a class and a pattern usually appears — scatter graphs reveal relationships that a table of numbers hides.
In a nutshell
Describe simple mathematical relationships between two variables in observational and experimental contexts and illustrate using scatter graphs
Learning cycle
Part 2 of 16
Learning cycle 1 of 2
Part 1 · Types of correlation
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 16
Learn
Types of correlation
Positive correlation: as one variable increases, so does the other (e.g. height and shoe size). Negative correlation: as one increases, the other decreases (e.g. car age and value). No correlation means no clear pattern.
Reset break
Part 4 of 16
Pause
That's sitting 1 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 16
Learn
Worked example
Given pairs (hours revised, test score): (1,40), (2,50), (3,65), (4,80). As hours increase, scores rise steadily — this is a positive correlation, and a line of best fit could estimate a score for 3.5 hours, around 72.
Quick check
Part 6 of 16
Quick check
Height and shoe size tend to increase together. What type of correlation is this?
Quick check
Part 7 of 16
Quick check
A car's value tends to fall as its age increases. What type of correlation is this?
Reset break
Part 8 of 16
Pause
That's sitting 2 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 16
Learning cycle 2 of 2
Part 2 · Reading a line of best fit
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 16
Learn
Reading a line of best fit
A line of best fit is drawn through the middle of the scattered points, roughly balancing points above and below. It can be used to estimate values not directly measured, but only within a sensible range of the data.
Quick check
Part 11 of 16
Reset break
Part 12 of 16
Pause
That's sitting 3 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 13 of 16
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 14 of 16
Game · Recall cards
Height and shoe size tend to increase together. What type of correlation is this?
Card 1 of 3
Mastery quiz
Part 15 of 16
Marked quiz
End of lesson quiz: Scatter graphs and correlation
3 questions, marked with the reasoning shown. No timer.
1. Height and shoe size tend to increase together. What type of correlation is this?
2. A car's value tends to fall as its age increases. What type of correlation is this?
3. What is a line of best fit used for?
Lesson round-up
Part 16 of 16
Lesson round-up
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Ask LunaPart 1 of 16 · Watch & discover
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Describe simple mathematical relationships between two variables in observational and experimental contexts and illustrate using scatter graphs