PAss Functional Skills

Averages and spread

Averages and spread for A Level Physics OCR: what it means, how to set the working out, and the questions it is asked in.
  • A Level
  • OCR
  • Physics
  • Spec P2 · P1
  • 4 min read
  • 9 revision boxes

Introduction

2 boxes
4 min read

What is averages and spread?

Listen to this box

Transcript

A short spoken summary of averages and spread and where it is used.

A spoken walk-through of averages and spread 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 averages and spread laid out step by step

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

The averages and spread reference table

Practise the routine version until it is automatic, then move to the multi-step questions.
Worth knowing: x2+5x+6=0x^2 + 5x + 6 = 0.
Term
Meaning
Example
Common slip
Marks
Row 1 column 1
Row 1 column 2
×10\times 10 moves every digit one column left
Row 1 column 4
Row 1 column 5
Row 2 column 1
Row 2 column 2
≈160\approx 160
Row 2 column 4
Row 2 column 5
Row 3 column 1
Row 3 column 2
34×25\frac{3}{4} \times \frac{2}{5}
Row 3 column 4
Row 3 column 5

Learning

5 boxes
3 steps

How to work with averages and spread

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 averages and spread 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: 49=7\sqrt{49} = 7.
Answer: x2+5x+6=0x^2 + 5x + 6 = 0
2 rules

Key facts: Averages and spread

This idea appears again in the higher-mark questions, so it is worth over-learning.
Worth knowing: ×10\times 10 moves every digit one column left.

  • Rule 1

    How averages and spread behaves in the 1st of the cases the specification names.
    34×25\frac{3}{4} \times \frac{2}{5}

  • Rule 2

    How averages and spread behaves in the 2nd of the cases the specification names.
    34×25\frac{3}{4} \times \frac{2}{5}
3 steps

How to work with averages and spread

Sketch the shape even when the question does not ask for one — it makes the next step obvious.
Worth knowing: ≈160\approx 160.
  1. Read the question and write down what is being asked for.
  2. Set out the working for averages and spread 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: 34×25\frac{3}{4} \times \frac{2}{5}.
Answer: 49=7\sqrt{49} = 7
3 rules

Key facts: Averages and spread

Practise the routine version until it is automatic, then move to the multi-step questions.
The layout below is the one the mark scheme expects.

Diagram showing averages and spread laid out step by step

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

  • Rule 1

    How averages and spread behaves in the 1st of the cases the specification names.
    x2+5x+6=0x^2 + 5x + 6 = 0

  • Rule 2

    How averages and spread behaves in the 2nd of the cases the specification names.
    x2+5x+6=0x^2 + 5x + 6 = 0
4 steps

How to work with averages and spread

The examiner marks the working, so a correct answer with no method still drops marks.
Worth knowing: a2+b2=c2a^2 + b^2 = c^2.
  1. Read the question and write down what is being asked for.
  2. Set out the working for averages and spread 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: 49=7\sqrt{49} = 7.
Answer: 34×25\frac{3}{4} \times \frac{2}{5}

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Examples

2 boxes
1 marks · worked

Worked example: averages and spread

Read the units in the question before you start; a converted unit is the most common slip.
4 marks · worked

Practice question 9: ≈160\approx 160

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 averages and spread laid out step by step

The same idea drawn out, so the method is visible.
Worth knowing: ≈160\approx 160.

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Common questions

How many marks is averages and spread usually worth?
Between one and four, depending on how many steps the question asks for.
Is this on the A Level Physics OCR paper?
Yes — it sits in the Data and information strand.