Lesson 2.02d

2.02d Informal interpretation of correlation Quiz: OCR Maths, Unit 12

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 2.02d, Informal interpretation of correlation: 20 multiple choice questions for the OCR Maths (H240), Unit 12: Data Presentation and Interpretation, written with Revision Ninja.

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The 20 questions

  1. What type of correlation exists if y increases as x increases on a scatter diagram?

    • Non-linear correlation
    • Positive correlation
    • Zero correlation
    • Negative correlation

  2. What does a standard deviation measure for a set of numerical data?

    • Data symmetry
    • Spread of data
    • Central tendency
    • Sample frequency

  3. Why is standard deviation calculated from a grouped frequency table considered an estimate?

    • Group sizes vary
    • Unknown data values
    • Frequencies are inaccurate
    • Calculators round values

  4. What statistic is defined as the square root of the variance?

    • Mean absolute error
    • Mean square deviation
    • Standard deviation
    • Interquartile range

  5. Which measure of spread is least affected by extreme values or outliers?

    • Range
    • Standard deviation
    • Variance
    • Interquartile range

  6. Standard deviation is formally defined as the root mean square deviation from which measure?

    • Mean
    • Median
    • Mode
    • Variance

  7. What term describes a scatter diagram where points show no clear trend or pattern?

    • Negative correlation
    • Weak correlation
    • Zero correlation
    • Strong correlation

  8. If sum of x is 50 for 10 observations, what is the mean value of x?

    • 5
    • 500
    • 0.2
    • 50

  9. High sales of ice cream correlate with high sunburn rates. What underlying factor explains this?

    • Hot weather
    • Sunburn effect
    • Direct causation
    • Ice cream effect

  10. If the variance of a dataset is 16, what is its standard deviation?

    • 256
    • 8
    • 2
    • 4

  11. A dataset has a standard deviation of zero. What must be true about the data?

    • Median is zero
    • Mean is zero
    • Values are positive
    • Identical data values

  12. If every value in a dataset is increased by 5, what happens to standard deviation?

    • Multiplies by 5
    • Remains unchanged
    • Increases by 5
    • Increases by 25

  13. If all values in a dataset are multiplied by 3, what happens to variance?

    • Remains unchanged
    • Increases by 3
    • Multiplied by 9
    • Multiplied by 3

  14. For data, sum of x squared is 200, sum of x is 30, and n is 5. Calculate variance.

    • 16
    • 4
    • 40
    • 10

  15. On a scatter graph, as variable A increases, variable B decreases. What correlation is present?

    • Positive correlation
    • Zero correlation
    • No correlation
    • Negative correlation

  16. Two distributions have identical means, but X has higher standard deviation than Y. Which has greater spread?

    • Neither distribution
    • Distribution Y
    • Both are equal
    • Distribution X

  17. For grouped data, class intervals are 0 to 10 and 10 to 20. What midpoint represents 10 to 20?

    • 20
    • 10
    • 5
    • 15

  18. Data set A has values 2, 4, 6. Data set B has values 12, 14, 16. Compare standard deviations.

    • They are equal
    • A is greater
    • B is greater
    • B is triple

  19. Given sum of squared deviations from the mean is 180 for 20 observations, find standard deviation.

    • 18
    • 9
    • 4.5
    • 3

  20. Correlation specifically measures the strength and direction of what type of relationship between two variables?

    • Non-linear
    • Exponential
    • Quadratic
    • Linear

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