1. Block Diagrams and Dot Plots
Mathematics
Block Diagrams and Dot Plots

2. Lesson Objectives The aim of this powerpoint is to help you…
to learn how to produce, read and interpret block diagrams
to learn how to produce, read and interpret dot plots

3. Block Diagrams
The data (discrete or categoric) is usually labelled along the bottom.
One block represents one item or person.
Block diagrams are the predecessors to bar charts but each block is individually visible within each column.

4. Block Diagrams - Example
Class 2P visit a farm.
When they get back from their visit, their teacher asks them which animal, out of all those seen at the farm during their visit, was their favourite.
These are the results:
The pupils draw a block diagram to show this.
Cow
Dog
Goat
Hen
Horse
Sheep 6 10 2 4 7 1

5. Block Diagrams - Example
Cow Dog Goat Hen Horse Sheep
Cow
Dog
Goat
Hen
Horse
Sheep 6 10 2 4 7 1

6. Dot Plots
Dot plots are associated with discrete data rather than categoric data.
The numeric data is usually labelled along the bottom.
One large filled circle represents one item or person.
Take care to ensure all the circles are the same size.

7. Dot Plots - Example
Class 2P were asked how many pets they each had at home. Their results were put in this dot plot.

8. Dot Plots - Example Q1. How many students have 2 pets? ANS: 7
Q1. How many students
have 2 pets?
[Hint: count dots in 2 column]
ANS: 7
Q2. How many students have fewer than 2 pets?
[Hint: count the dots in the 0 and 1 columns]
ANS. 20
Q3. How many students are there in class 2P?
[Hint: count ALL the dots]
ANS. 30

9. What next? Print out and read through the notes called Data5.
Work through page 6 ONLY of the MyMaths lesson called Introducing Data which can be found at:
Work through the MyMaths lesson called DotPlots (ignoring the questions on averages and range) which can be found at:
Now answer the two sets of tasks on the Data5 notes pages
Further practice is available by working through the worksheet: Block1.xlsx
Move on to the Data-6 powerpoint