Lesson 2.02h

2.02h Outliers and data cleaning Quiz: OCR Maths, Unit 12

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 2.02h, Outliers and data cleaning: 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. Under the IQR rule, an outlier is further from the nearer quartile than what distance?

    • 3.0 × IQR
    • 1.0 × IQR
    • 1.5 × IQR
    • 2.0 × IQR

  2. Under the standard deviation rule, a value is an outlier if it is more than how far from the mean?

    • 3 interquartile ranges
    • 1 standard deviation
    • Half the range
    • 2 standard deviations

  3. According to the OCR specification, an outlier is further from the mean than how many standard deviations?

    • 1 standard deviation
    • 2 standard deviations
    • 1.5 standard deviations
    • 3 standard deviations

  4. An age value of 230 years is recorded in a survey. How should this data point be classified?

    • Genuine outlier
    • Data entry error
    • Valid value
    • Missing data

  5. On a standard box plot, how are individual outliers usually represented?

    • Separate points
    • Extended whiskers
    • Dashed lines
    • Shaded boxes

  6. Before removing an outlier from a clean data set, what action should always be taken first?

    • Automatically delete it
    • Investigate its cause
    • Replace with zero
    • Change to mean

  7. Which measure is resistant to outliers?

    • The standard deviation
    • The range
    • The mean
    • The median

  8. The values 1 to 9 together with a value of 40 are recorded. Using the 1.5 x IQR rule, which value is an outlier?

    • 1
    • 40
    • 9
    • 5

  9. Q3 = 30 and IQR = 12. Using the 1.5 x IQR rule, what is the upper outlier boundary?

    • 36
    • 42
    • 48
    • 54

  10. A data set has mean 25 and standard deviation 3. Which value is an outlier by the 2 standard deviation rule?

    • 32
    • 28
    • 20
    • 30

  11. Heights of 1.8 m and 180 m are recorded in a survey. What type of error is 180 m?

    • Random variation
    • Sampling error
    • Non-response bias
    • Units error

  12. When data contains extreme positive skew from a high outlier, which measure of location is best?

    • Mean
    • Median
    • Midrange
    • Mode

  13. What is the process of removing errors and handling missing values in a data set called?

    • Data cleaning
    • Data collection
    • Data sampling
    • Data extrapolation

  14. A box plot whisker ends at 48 and a point at 60 is plotted separately. What is that point?

    • A possible outlier
    • The median
    • The mean
    • The upper quartile

  15. What happens to both the mean and standard deviation when removing a high outlier?

    • Standard deviation increases
    • Mean increases
    • Both decrease
    • Both increase

  16. A data set has mean 50 and standard deviation 5. Is 62 an outlier using the 2 SD rule?

    • Yes, 1.2 SDs away
    • No, 2.4 SDs away
    • Yes, 2.4 SDs away
    • No, 1.2 SDs away

  17. What should be done if the IQR rule and 2 SD rule give conflicting outlier decisions?

    • Always use 2 SD
    • Discard the data point
    • Always use IQR
    • State and justify rule

  18. A living patient has a recorded heart rate of 0. How should this data point be treated?

    • Replace with mean
    • Record as error
    • Ignore without recording
    • Keep as valid

  19. Which statistical measure makes the interquartile range more robust against outliers than standard deviation?

    • Mean
    • Total frequency
    • Variance
    • Quartiles

  20. What is the first step in best practice when handling an outlier in a data set?

    • Replace with mean
    • Ignore completely
    • Delete it immediately
    • Investigate its cause

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