Association — Grade 8 Math, what it means and where it is taught
A pattern linking the two variables.
Taught in Grade 8 Math.
Where it is taught
Practise this idea
11 questions in the course bank use Association, in Scatter Plots & Association, Two-Way Tables, Sampling, Simulation & Inference. The first 8 are below; the rest are in those units.
Problem 1
As study time increases, test scores increase. This is
- a positive association
- a negative association
- no association
- a causal proof
Worked answer
a positive association
Up together means positive
Nothing here proves cause
Problem 2
As the age of a car increases, its value decreases. This is
- a negative association
- a positive association
- no association
- a cluster
Worked answer
a negative association
Opposite directions means negative
Problem 3
Ice cream sales and sunburn cases rise together. The best explanation is
- hot weather drives both
- ice cream causes sunburn
- sunburn causes ice cream sales
- the data must be wrong
Worked answer
hot weather drives both
Hot weather increases both independently
That is a confounding variable
Association is not causation
Problem 4
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 5
Two plots both show positive association. In plot A the dots are tight to the line; in plot B they are widely scattered. Which is stronger?
- A
- B
- They are equally strong
- Cannot be determined
Worked answer
A
Closeness to the pattern measures strength
A is tighter, so A is stronger
Problem 6
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 7
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 8
A study finds a strong positive association between number of firefighters sent and damage done to a building. Should fewer firefighters be sent? Answer yes or no.
Worked answer
no
Bigger fires get more firefighters
Bigger fires also cause more damage
Fire size is the confounder
Sending fewer would make things worse