GCSE · Data representation

Time seriesExam-style questions

Measurements plotted against time and joined in order — why joining is legitimate here but not on a scatter graph, how to describe a trend so it earns the mark, how to spot seasonal variation and use it to predict the next quarter, and why predicting far beyond the data is worthless.

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11 questions · GCSE (Higher) level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 1Level 2Level 3Level 4Level 5
  1. 1
    The time-series graph shows the number of new members who joined Fairfield Swimming Club in each quarter from 2023 to 2025.

    Quarter 1 on the graph is the first quarter of 2023, quarter 5 is the first quarter of 2024 and quarter 9 is the first quarter of 2025.123456789101112131234567891011121314Quarter (1 = Q1 of 2023)New members(a) Rob says: "The graph just goes up and down, so there is no overall trend."

    Explain why Rob is wrong. You must refer to figures from the graph.

    (b) Explain why this graph should not be used to predict the number of new members who will join in quarter 1 of 2040.
    Level 4 · 5 marksTry it
  2. 2
    A gift shop on a seaside promenade employs part-time staff. The time-series graph shows the number of part-time staff it employed in each quarter from 2023 to 2025.

    Quarter 1 on the graph is the first quarter of 2023, quarter 5 is the first quarter of 2024 and quarter 9 is the first quarter of 2025.123456789101112131234567891011121314Quarter (1 = Q1 of 2023)Part-time staff(a) Describe the seasonal variation shown by the graph.

    (b) Chloe says: "The number of part-time staff the gift shop employs is increasing."

    Is Chloe correct? You must give a reason for your answer.
    Level 4 · 4 marksTry it
  3. 3
    The table shows the electricity cost, in pounds, for a small factory in each quarter of 2023 and in the first three quarters of 2024.
    Electricity cost (£)Quarter 1Quarter 2Quarter 3Quarter 4
    202314209809101310
    202415301060970—
    The total electricity cost for the whole of 2024 was £4970.

    (a) Work out the electricity cost for quarter 4 of 2024.

    (b) The factory manager says: "In 2024 the cost fell from £1530 in quarter 1 to £970 in quarter 3, so our electricity is getting cheaper."

    Explain why the manager may be wrong.
    Level 4 · 4 marksTry it