Scatter plot — Grade 8 Math, what it means and where it is taught
A graph of paired data, one dot per case.
Taught in Grade 8 Math.
Where it is taught
What uses it later
This idea is needed for:
- Line of best fit — A straight line summarising a linear pattern in a scatter plot.
Practise this idea
7 questions in the course bank use Scatter plot, in Scatter Plots & Association, Statistics: Centre, Spread & Displays.
Problem 1
The dots on a scatter plot lie close to a straight band. The form is
- linear
- curved
- clustered
- random
Worked answer
linear
Close to a straight line means linear form
Problem 2
A scatter plot has dots falling steeply from upper left to lower right, tightly packed. Describe the association in three words.
Worked answer
strong negative linear
Tightly packed: strong
Falling: negative
Straight band: linear
Problem 3
A scatter plot of a class shows 24 dots. How many students are in the class?
Worked answer
24
One dot per student
24 students
Problem 4
A point at the far right of a scatter plot lies exactly on the pattern. It is
- not an outlier
- an outlier
- the mean
- a cluster
Worked answer
not an outlier
This point follows the trend
So it is not an outlier, however extreme its x value
Problem 5
A scatter plot of shoe size against height shows a positive association. Does a large shoe size guarantee a tall person? Answer yes or no.
Worked answer
no
Positive means taller on average
Individual cases still vary
So no guarantee
Problem 6
A scatter plot of price against size for houses shows two separate clouds. The likeliest reason is
- two different neighbourhoods are mixed together
- houses have two prices
- the data is random
- there is no association
Worked answer
two different neighbourhoods are mixed together
Each group follows its own pattern
Splitting the plot would show two clean trends
Problem 7
Which display best compares three groups at once?
- Side-by-side box plots
- A single dot plot
- A pie chart
- A scatter plot
Worked answer
Side-by-side box plots
Box plots show the five-number summary
Placing them side by side compares groups directly