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Mathematics · GCSE

Probability and statistics
GCSE Mathematics knowledge mat

What the Average Hides

Why 'without replacement' changes the whole calculation, and when the mean is the wrong average to quote. Probability with a tree diagram drawn without replacement; which average and why, with a box plot; samples, charts, Venn diagrams and correlation; six questions to ask before you calculate anything; a worked probability without replacement. Twelve terms to define, a model answer on a mean far above a median, and the misconceptions that cost marks.

£3.99All 4 GCSE Mathematics knowledge mats, one landscape sheet each

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One purchase, all 4 GCSE Mathematics sheets, £3.99 for the set: this one · Number, ratio and proportion · Algebra, graphs and sequences · Geometry, Pythagoras and trigonometry

One purchase covers the school that buys it. Print it, copy it, hand it round your department. Not for passing to other schools or uploading anywhere.

PDF download, ready straight after payment. Downloading it ends the 14-day right to cancel; a file that is faulty or not as described is always refunded. Refunds

Read before publication by the serving head of that department and by senior leaders, in school.

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Schools that have bought from Empower Educators include Nottingham High School, Northampton High School GDST and Sutton Valence School.

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    Cover of What the Average Hides

    One landscape A4 page on one topic, built around one idea a class can hold onto. It carries a tree diagram without replacement, which average and why, a box plot, sampling, charts, Venn diagrams, correlation and a worked probability, then the vocabulary, a worked exam-style answer and the misconceptions that cost marks.

    No photographs, on purpose: there is no archival photograph of a percentage, and a stock image of a calculator would make the sheet worse. Every figure is drawn in code for the sheet — a bar model, a graph, a tree diagram — so nothing on it is licensed from anybody and nothing is AI-generated. Every claim is sourced to the DfE subject content and its Appendix of formulae, and nothing is reproduced from a past paper, a textbook or a specification.

    Sold by subject: all four mathematics sheets for one price. A knowledge organiser stores a unit and is revised from afterwards; this is meant to be on the table while the work is happening.

    Written to
    The DfE GCSE mathematics subject content (DFE-00233-2013) and its Appendix of formulae. No photographs: every figure is drawn in code for the sheet, so nothing on it is licensed from anybody
    Intended for
    mathematics teachers. On the desk during the lesson, not a student revision guide
    Extent
    One landscape A4 sheet · 8 sections

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    Real pages, straight from the PDF

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    Contents

    What’s on the sheet

    The sections on the sheet, in the order they appear.

    01Probability, and its one rule
    02Which average, and why
    03Samples, charts and correlation
    04Questions to ask before you calculate anything
    05Work a probability without replacement
    06Glossary
    07Use this mat
    08Common misconceptions
    Next: Inheritance and evolution knowledge mat

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    Your download is ready straight after payment. Downloading it ends the 14-day right to cancel; a file that is faulty or not as described is always refunded.Refunds