Lesson L4

L4 Outliers and cleaning data Quiz: AQA Maths, Unit 11

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson L4, Outliers and cleaning data: 20 multiple choice questions for the AQA Maths (7357), Unit 11: Statistics, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. What is the term for a data value that lies unusually far from other observations?

    • Variance point
    • Outlier
    • Anomalous median
    • Residual error

  2. Under the 1.5 x IQR rule, what upper boundary defines an outlier?

    • Q1 + 1.5 IQR
    • Q3 + 3 IQR
    • Q3 + IQR
    • Q3 + 1.5 IQR

  3. What is the correct first step when dealing with missing values in raw data?

    • Replace with mean
    • Delete all rows
    • Investigate the cause
    • Replace with zero

  4. What should be done if an outlier is confirmed to be a typing error?

    • Keep unchanged
    • Ignore the error
    • Correct the error
    • Replace with mean

  5. What effect does a single extreme outlier have on the mean of a data set?

    • Decreases variance
    • Changes the mode
    • Has no effect
    • Distorts towards outlier

  6. For the data 3, 5, 6, 7, 8, 9 and 40, which value is an outlier using the 1.5 IQR rule?

    • 3
    • 8
    • 9
    • 40

  7. For the data 3, 5, 6, 7, 8, 9 and 40, what is the mean including all values, to 1 decimal place?

    • 11.1
    • 7.0
    • 78
    • 6.3

  8. For the data 3, 5, 6, 7, 8, 9 and 40, what is the mean after removing the outlier 40, to 1 decimal place?

    • 6.3
    • 7.0
    • 9.0
    • 11.1

  9. For the data 3, 5, 6, 7, 8, 9 and 40, what is the median after removing the outlier 40?

    • 6.5
    • 7
    • 6
    • 7.5

  10. What should be investigated first before deciding how to handle missing data values?

    • Data skewness
    • Sample standard deviation
    • Cause of missingness
    • Interquartile range

  11. An adult height recorded in metres is listed as 170. What action is required?

    • Ignore the value
    • Keep as outlier
    • Remove data point
    • Check and correct

  12. Which statistical diagram is specifically designed to highlight outliers clearly using fences?

    • Cumulative frequency graph
    • Pie chart
    • Histogram
    • Box plot

  13. How should a genuine, non-erroneous extreme value in a data set be treated?

    • Replace with mean
    • Set to zero
    • Delete immediately
    • Retain and report

  14. Quartiles Q1 = 12 and Q3 = 20 are found for a data set. What is the upper fence for outliers?

    • 28
    • 32
    • 24
    • 36

  15. With Q1 = 12 and Q3 = 20, which of these values is an outlier?

    • 10
    • 25
    • 30
    • 33

  16. What effect does a single extreme outlier typically have on the standard deviation?

    • Makes it negative
    • Has no effect
    • Decreases it to zero
    • Increases it significantly

  17. An exam mark out of 100 is recorded in a database as 105. What is required?

    • Keep as outlier
    • Delete student record
    • Correct the error
    • Ignore the value

  18. Why are the median and IQR preferred for summarised data containing extreme outliers?

    • Always positive integers
    • Easier to calculate
    • Resistant to outliers
    • Use every value

  19. In the data set 1, 2, 3, 4, 100, which average is heavily distorted by the value 100?

    • Mode
    • Median
    • Lower quartile
    • Mean

  20. When outliers are removed during data cleaning, what must be documented in the report?

    • Population median
    • Reason for removal
    • Confidence intervals
    • Sample variance formula

All AQA Maths quizzes