Graphics Diagrams

Graphs We can present data in a graphical form as it is easier to see what is going on, or to spot patterns, rather than looking at raw numbers in a table or in a spreadsheet. Graphs are visual images which are quick and easy to read.

Raw data Raw data is collected and recorded in a table. Eye colour A simple table is quite easy to read. What is the most popular eye colour for this class? Blue Black Brown Grey Hazel Green Class One 8 3 15 2 4

Data from a table can be presented in many ways. There are 5 main types of graphs; 1. pictogram 2. bar chart. 3. comparative graph 4. pie chart 5. line graph

Pictogram: You used pictograms in ‘graphstart’. This is a simple way of representing data with a picture. 3 Y axis This tells us the number of pets. 2 1 dog cat fish rabbit X axis. This tells us the type of pets.

PICTOGRAMS Can you think what the advantages and disadvantages of a pictogram may be? * Easy to read * simple data * Quick * limited topics * All languages * suits smaller numbers

Bar Chart A bar chart uses columns or blocks to show data values. This type of chart is useful for showing bigger numbers and for making quick comparisons. Y axis – usually represents the values tat change. Children with eye colour. X axis – represents the category choices, the data that does not change.

Comparative Chart However, if you survey more classes, there is more data to wade through....... Now which is the most popular eye colour? It is much harder to spot the answers. Blue Black Brown Grey Hazel Green Class One 8 3 15 2 4 Class Two 10 1 14 6 Class Three 18 Class Four 9 5 7

Comparative graph A comparative graph is used to compare sets of data. It groups results for the same category.

PIE CHART NOT that sort of PIE!!!! A pie chart is a circle made from segments. Each segment represents a proportion. NOT that sort of PIE!!!!

Pie chart THIS type of PIE! The proportions of a pie chart are usually shown as a percentage. This is called a legend – it uses a colour code to show the categories.

Pie Chart Pie charts do not show exact values, but percentages. They are really useful when comparing a large sample with a small sample. It would be difficult, as a bar chart, to compare class eye colour with a top value of 30 children to a whole school survey, where there will be over 200 answers.

Line Graph A line graph is used when the value being measured is the same. It is similar to a bar chart, but samples data at intervals. Line graphs can track when values are high or low. One example is a weather chart, showing the sunshine or rainfall for the year. Each month would be an interval measure. Business use line graphs to track their sales.

Can you remember the five main types of graphs? Each graph type has it’s own advantages and disadvantages. You need to think about your purpose and audience before choosing which style to use. Can you remember the five main types of graphs?