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

**Statistics**

**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.

**Data Handling**

- 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

**Averages**

**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.

**Pie Charts**

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

**Graphs**

- Accurate scale

**Scatter Graph**

- 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

**Line Graph**

- 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

**Stem and Leaf**

That's the end of the topic!

Drafted by Bonnie (Mathematics)