IGCSE/GCSE Mathematics - Statistical Representation

When it comes to IGCSE/GCSE Maths, can you distinguish qualitative data, quantitative data, continuous data and discrete data?

Qualitative Data

• Not a number, often descriptive, e.g. colour/make of car.

Quantitative Data

• Data with numbers in it, e.g. time, height, shoe size, age.
• Can be discrete or continuous.
• Continuous Data - Data that can take on any value/range, e.g. time/height.
• Discrete Data - Data where there are no in-between values, specific, e.g. how many children you have.

Bivariate Data

• Combination of two variables (values), e.g. age + height.

Primary Data

• Data you have collected yourself, e.g. survey.
• It can be expensive or time consuming.
• Better understanding of the data.

Secondary Data

• Information from somebody else, e.g. internet.

• No overlaps
• Simple Understandable language or specific words
• Short questions with precise answers
• Tick Boxes
• Avoid open-ended questions
• Avoid leading questions or Unbiased question
• Time frames

Mean

• Add all values and ÷ by quantity of values, total data ÷ total frequency.
• e.g. 1 ,2 ,2 ,4 ,6 ,6 ,7 ,8
• total = 36
• quantity of values = 8
• mean = 36/8 = 4.5

Median

• Align numbers in ascending order and find the middle number.
• Middle number = ½(N+1), N = total amount of data
• If there is no middle number (even data), + the middle numbers then ÷ 2
• e.g. 1, 2, 2, 4, 6, 6, 7, 8 ⟶ median = (4+6) ÷ 2 = 5

Mode

• Most common, highest frequency.
• e.g. 1, 3, 3, 4, 3, 6, 7 → mode = 3

Range

• Measure of spread.
• It is used to compare consistency.
• Lower the range, the higher the consistency.

• 360/𝑓 = 𝑥 = degrees per 𝑓
• Comparative Bar Chart:

• Accurate scale

• Compares 2 sets of data.
• Comparison can be used to look for connections between data, called correlation
• Positive correlation = e.g. More illness + more absences
• Negative correlation = e.g. More students + less vacancies in schools
• No correlation = e.g. Pencil case colour + hair length

• Join each point individually with straight lines.
• Used to show trend over a number of days or hours.
• Plotted as a series of points.
• The end of the line graph does not have to join the axis.
• Trend is the general direction of movement or change

That's the end of the topic!

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Drafted by Bonnie (Mathematics)