levo

Quantitative Skills for Economics

Ratios, percentages, averages, graphs, index numbers and real values

  • 6 things to know
  • Components 01, 02 and 03

Overview

Recall questions on concentration ratios, ratios and fractions, percentage and percentage point changes, mean and median, reading line and scatter graphs, index numbers, real values and correlation.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Numbers

A market is worth £250 million a year and the three largest firms sell £60 million, £45 million and £20 million. Calculate the three-firm concentration ratio.

Numbers

A price index falls from 132 to 130 over a year, with the base year set at 100. What does this tell you about prices during the year, and relative to the base year?

Numbers

A price index rises from 125.0 to 130.0 over a year. Calculate the rate of inflation.

Numbers

Real GDP rises from £2,400 billion to £2,472 billion in a year. Calculate the rate of economic growth.

Numbers

Nominal GDP is £2,600 billion and the GDP deflator is 130, with the base year at 100. Calculate real GDP at base-year prices.

Key term

Real GDP falls by 4% in one year and then rises by 5% the next. What is the overall percentage change across the two years?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    A market is worth £250 million a year and the three largest firms sell £60 million, £45 million and £20 million. Calculate the three-firm concentration ratio.

    Model answer

    Their combined sales are £125 million, so the three-firm concentration ratio is £125m ÷ £250m = 50% of the market.

  2. 2

    A country exports £84 billion of goods and imports £126 billion. Express exports to imports as a ratio in its simplest form, and state the fraction of import spending covered by export earnings.

    Model answer

    Dividing both figures by 42 gives a ratio of 2:3, so exports cover two thirds of import spending.

  3. 3

    Real GDP rises from £2,400 billion to £2,472 billion in a year. Calculate the rate of economic growth.

    Model answer

    The increase is £72 billion, so growth is £72bn ÷ £2,400bn = 3.0%.

  4. 4

    Real GDP falls by 4% in one year and then rises by 5% the next. What is the overall percentage change across the two years?

    Model answer

    Applying the changes in turn gives 0.96 × 1.05 = 1.008, so output is 0.8% higher than it was two years earlier.

  5. 5

    Unemployment falls from 8% of the labour force to 6%. State the fall in percentage points and calculate the percentage fall in the unemployment rate.

    Model answer

    It is a fall of 2 percentage points, which is a 2 ÷ 8 = 25% fall in the rate itself.

  6. 6

    Seven workers earn weekly wages of £300, £340, £360, £380, £420, £460 and £1,100. Calculate the mean and the median, and state which better represents a typical worker.

    Model answer

    The wages total £3,360, so the mean is £3,360 ÷ 7 = £480 and the median is the fourth value in order, £380; the single high wage skews the mean upwards, so the median is the better guide to a typical worker.

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.

1Closed book
2Open book
3Closed book

The 3-step method, run for you

Answer cold, learn it, then prove it stuck. Levo tracks the jump between your first attempt and your last.

Introduction to Microeconomics
Microeconomics: The Role of Markets
Microeconomics: Business Objectives
Microeconomics: Market Structures

Cram a whole paper in one sitting

Sort every topic into what you know and what you do not, then drill only the weak ones.

An of demand.
extensionincreaseelasticity

Blank Blitz makes facts automatic

Rapid timed gap-fills on the terms and numbers you need to recall without thinking.

AAt 0% nothing is levied at all.
BAt 100% there is no reward left for the taxed activity.
CThe activity ceases and there is nothing to tax.

Build It gets the exam shape right

Assemble a full-mark answer from its marking points, in the order an examiner wants them.

Economic growth means an increase in real output over a period.
TrueFalse

Test It catches misconceptions

Spot the fault in a statement. The traps are the mistakes students actually make.

721941163128510

Brain Breaks between sessions

Short focus games to reset attention, so the next set lands better than the last.

Every question in Quantitative Skills for Economics, on a schedule.

Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.

Or £46 a year, about £3.83 a month. Cancel anytime.