Lesson S6

S6 Scatter graphs, correlation and lines of best fit Quiz: AQA Maths, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson S6, Scatter graphs, correlation and lines of best fit: 20 multiple choice questions for the AQA GCSE Maths (8300), Unit 6: Statistics, written with Revision Ninja.

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The 20 questions

  1. What does a positive correlation mean?

    • As one variable increases, the other tends to increase
    • There is no relationship at all
    • The data are categorical
    • As one variable increases, the other decreases

  2. What does correlation NOT indicate?

    • Causation
    • Association
    • Strength
    • Direction

  3. What does a line of best fit do?

    • Shows only the mean of the x and y values
    • Passes close to the points to show the trend
    • Joins every point exactly, passing through all of them
    • Passes through the origin, so it must start at zero

  4. What does interpolation mean?

    • Estimating outside the range of the data
    • Calculating the mean
    • Plotting the median
    • Estimating within the range of the data

  5. What does extrapolation mean?

    • Estimating beyond the range of the data
    • Finding the mode
    • Estimating within the range of the data
    • Drawing a histogram

  6. What does a strong negative correlation look like on a scatter graph?

    • Points lie close to a horizontal line
    • Points lie close to a downward sloping line
    • Points are spread randomly
    • Points form a circle

  7. What does no correlation mean?

    • All the values are equal
    • The points lie on a straight line
    • The points show no clear pattern
    • The graph is a bar chart

  8. What is a scatter graph used to show?

    • Grouped continuous data only, shown in a frequency table
    • Univariate categorical data, with one variable for each item
    • Bivariate data, with two variables for each item
    • A time series with one variable recorded at each point

  9. A line of best fit passes through (2, 10) and (6, 26). What is its gradient?

    • 8
    • 4
    • 2
    • 16

  10. A line of best fit is y = 4x + 2. What is the predicted value of y when x = 5?

    • 4
    • 22
    • 18
    • 20

  11. Children's shoe size and reading ability are correlated. Which explanation is most sensible?

    • Shoe size causes reading ability
    • Reading ability causes shoe size
    • There is no reason for the correlation
    • Age is a common factor that affects both

  12. A prediction is made for x = 12 using data only from x = 1 to x = 10. What is this called?

    • Sampling
    • Interpolation
    • Extrapolation
    • Correlation

  13. A prediction is made for x = 4 using data from x = 1 to x = 10. What is this called?

    • Interpolation
    • Bias
    • Sampling error
    • Extrapolation

  14. A line of best fit passes through (0, 3) and (4, 11). What is the predicted value at x = 7?

    • 17
    • 21
    • 14
    • 11

  15. Revision time and marks have a strong positive correlation. Which conclusion is valid?

    • Revision may be linked to higher marks, but correlation alone does not prove causation
    • A positive correlation means revision is harmful, so pupils should stop
    • The points are close together, so causation is proven by the strong trend
    • Revision always causes higher marks for every single pupil in the class

  16. What is an outlier on a scatter graph?

    • The point closest to the line of best fit drawn
    • A point far away from the general pattern
    • The mean point of the whole scatter graph data
    • The point at the origin, which is always an outlier

  17. (H) A line of best fit passes through (1, 5) and (5, 13). What is its equation?

    • y = 3x + 2
    • y = x + 4
    • y = 2x + 3
    • y = 2x + 5

  18. (H) Using y = 2x + 3, what is the estimated y when x = 10?

    • 23
    • 30
    • 20
    • 13

  19. (H) A correlation coefficient of r = -0.9 is found. Which description is correct?

    • Strong positive correlation
    • No correlation
    • Strong negative correlation
    • Weak positive correlation

  20. (H) A line of best fit has gradient 0.5. By how much does y change for a 10-unit increase in x?

    • 5
    • 50
    • 10
    • 0.5

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