PAss Functional Skills

Curved graphs

Curved graphs for GCSE Statistics AQA Foundation: what it means, how to set the working out, and the questions it is asked in.
  • GCSE
  • AQA
  • Statistics
  • Foundation
  • Spec A6
  • 7 min read
  • 7 revision boxes

Introduction

2 boxes
2 min read

What is curved graphs?

Listen to this box

Transcript

A short spoken summary of curved graphs and where it is used.

A spoken walk-through of curved graphs before you read the notes.
Sketch the shape even when the question does not ask for one — it makes the next step obvious.
The layout below is the one the mark scheme expects.

Diagram showing curved graphs laid out step by step

The same idea drawn out, so the method is visible.
3 rows

The curved graphs reference table

Practise the routine version until it is automatic, then move to the multi-step questions.
Worth knowing: ≈160\approx 160.
Term
Meaning
Example
Common slip
Row 1 column 1
Row 1 column 2
34×25\frac{3}{4} \times \frac{2}{5}
Row 1 column 4
Row 2 column 1
Row 2 column 2
×10\times 10 moves every digit one column left
Row 2 column 4
Row 3 column 1
Row 3 column 2
49=7\sqrt{49} = 7
Row 3 column 4
Row 4 column 1
Row 4 column 2
a2+b2=c2a^2 + b^2 = c^2
Row 4 column 4

Learning

3 boxes
4 steps

How to work with curved graphs

The examiner marks the working, so a correct answer with no method still drops marks.
  1. Read the question and write down what is being asked for.
  2. Set out the working for curved graphs in the order the method gives.
  3. Substitute the values and simplify.
  4. Check the answer against an estimate before writing it down.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: ×10\times 10 moves every digit one column left.
Answer: a2+b2=c2a^2 + b^2 = c^2
2 rules

Key facts: Curved graphs

This idea appears again in the higher-mark questions, so it is worth over-learning.
The layout below is the one the mark scheme expects.

Diagram showing curved graphs laid out step by step

The same idea drawn out, so the method is visible.
Worth knowing: 34×25\frac{3}{4} \times \frac{2}{5}.

  • Rule 1

    How curved graphs behaves in the 1st of the cases the specification names.
    49=7\sqrt{49} = 7

  • Rule 2

    How curved graphs behaves in the 2nd of the cases the specification names.
    ×10\times 10 moves every digit one column left
3 steps

How to work with curved graphs

Sketch the shape even when the question does not ask for one — it makes the next step obvious.
Worth knowing: 49=7\sqrt{49} = 7.
  1. Read the question and write down what is being asked for.
  2. Set out the working for curved graphs in the order the method gives.
  3. Substitute the values and simplify.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: x2+5x+6=0x^2 + 5x + 6 = 0.
Answer: ≈160\approx 160

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Examples

2 boxes
4 marks · worked

Worked example: curved graphs

Work through the method one line at a time and write down what changes at each step.
Worth knowing: x2+5x+6=0x^2 + 5x + 6 = 0.
2 marks · worked

Practice question 7: ×10\times 10 moves every digit one column left

Read the units in the question before you start; a converted unit is the most common slip.
The layout below is the one the mark scheme expects.

Diagram showing curved graphs laid out step by step

The same idea drawn out, so the method is visible.

Practice bank

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Common questions

How many marks is curved graphs usually worth?
Between one and four, depending on how many steps the question asks for.
Is this on the GCSE Statistics AQA Foundation paper?
Yes — it sits in the Forces and motion strand.