AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
Students should be able to use a scatter diagram to identify a correlation…
Full specification wording
The effect of lifestyle on some non-communicable diseases: Students should be able to use a scatter diagram to identify a correlation between two variables in terms of risk factors.
A scatter diagram plots one variable on the x-axis and another on the y-axis, with each point representing one individual or one group.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 9 of 9
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
A scatter diagram plots one variable on the x-axis and another on the y-axis, with each point representing one individual or one group. If the points lie close to a straight line rising from left to right, there is positive correlation: as one variable increases, the other tends to increase. A falling pattern shows negative correlation, and a random scatter shows no correlation. In risk-factor studies, a positive correlation might link the number of cigarettes smoked per day with the risk of lung cancer. Correlation shows an association, not proof that one variable causes the other, because other factors may be involved.
What earns the marks
- Identifies the variables on the x-axis and y-axis and states what each represents.
- Recognises positive correlation when both variables increase together.
- Recognises negative correlation when one variable increases as the other decreases.
- Recognises no correlation when points are randomly scattered.
- Describes the strength of correlation as strong or weak based on how closely points fit a line.
- Explains that correlation does not prove causation and that other risk factors may contribute.
Common mistakes and how to put them right
Calling a scatter diagram a line graph and joining the points.
Put it right by leaving the points unjoined and describing the pattern.
Claiming that correlation proves cause.
Put it right by stating that correlation shows an association only.
Mixing up the axes.
Put it right by checking axis labels before describing the relationship.
Exam tips
- State the direction of the correlation first, then its strength, then link it to the risk factor.
- Use the phrase positive correlation or negative correlation rather than saying the line goes up or down.
- If asked about cause, mention that other lifestyle or genetic factors could also affect the disease.
Try the lesson
The start of the The effect of lifestyle on some non-communicable diseases: Students should be able to use a scatter diagram to identify a correlation between two variables in terms of risk factors. lesson, made from checked teaching notes for this specification point.
Have a go first
A scatter diagram shows the number of cigarettes smoked per day on the x-axis and the number of cases of lung cancer on the y-axis. The points form a band that rises from bottom-left to top-right. Which type of correlation does this scatter diagram show?
Listen
A scatter diagram plots one variable on the x-axis and another on the y-axis, with each point representing one individual or one group. If the points lie close to a straight line rising from left to right, there is positive correlation: as one variable increases, the other tends to increase. A falling pattern shows negative correlation, and a random scatter shows no correlation. In risk-factor studies, a positive correlation might link the number of cigarettes smoked per day with the risk of lung cancer. Correlation shows an association, not proof that one variable causes the other, because other factors may be involved. A strong answer earns marks for these points. Identifies the variables on the x-axis and y-axis and states what each represents. Recognises positive correlation when both variables increase together. Recognises negative correlation when one variable increases as the other decreases. Recognises no correlation when points are randomly scattered. A common slip: Calling a scatter diagram a line graph and joining the points. Instead, leaving the points unjoined and describing the pattern. Exam tip: State the direction of the correlation first, then its strength, then link it to the risk factor.
Key words
Say what each word means before you turn the card.
Scatter diagram interpretation
Try answering aloud or in your head before turning the card.
Risk factors and disease
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Evidence and causation
Try answering aloud or in your head before turning the card.
See every definition
- Scatter diagram interpretation
- Reading the pattern of points on a scatter diagram, where one variable is on the x-axis and another on the y-axis, to identify positive, negative or no correlation and describe its strength.
- Risk factors and disease
- In risk-factor studies, a positive correlation might link the number of cigarettes smoked per day with the risk of lung cancer, but other factors may be involved.
- Evidence and causation
- Correlation shows an association, not proof that one variable causes the other, because other factors may be involved.
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