Page 94 - Knowledge Organiser Yr8 24-25

Knowledge Base: Mathematics TOPIC 13: Visualising Data Year 8 | Autumn Term 1
By the end of this topic you should be able to:
• Recognise different types of data
• Create bar charts and frequency diagrams
• Create and interpret line graphs
• Understand scatter graphs and different types of correlation
• Create and interpret stem and leaf diagrams
• Interpret pie charts
• Find the mean, median, mode and range
Secondary data
Continuous data Categorical data Bar chart Frequency Table Line graph
Data which you did not collect yourself
Information from a book or the internet
Language
Meaning
Example
Primary data
Data which you collect yourself
The results of a survey or experiment which you carried out
Discrete data
Data which is collected by counting
The number of pets or brothers and sisters that you have
Data which is obtained by measuring
Data which is obtained by describing
Used to represent categorical or discrete data
Used to show the amount of data in each group
A graph that shows plotted points joined by straight lines
Your height, weight or age The colour of your eyes
Mean: the sum of the values divided by the number of items
Median: the middle value when the data is put in order
Mode: the most common value in a set of data
Scatter diagram
A graph which allows you to see patterns in pairs of data
A graph of height versus arm-span for students in your class
Stem and leaf diagram
A diagram which allows you to see the shape of the distribution of data while retaining the actual numerical values of the data
Pie chart
A diagram in which the data is represented in a circular graph; the proportions of the different categories are represented visually
Average Range
A measure of the ‘typical value’ of data The mode, median and mean are averages A measure of the spread of data Range of-5, 1, 2, 4 and 9 is 9 – (-5) = 14
Worked examples
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