MATHEMATICSBlock Diagrams and Dot Plots

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

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.

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

Block Diagrams - Example

Cow Dog Goat Hen Horse Sheep

Cow Dog Goat Hen Horse Sheep

6 10 2 4 7 1

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.

Dot Plots - Example• Class 2P were asked how many pets they each had at

home. Their results were put in this dot plot.

0 1 2 3

Dot Plots - ExampleQ1. 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

0 1 2 3

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:

• http://app.mymaths.co.uk/350-resource/introducing-data

• Work through the MyMaths lesson called DotPlots (ignoring the questions on averages and range) which can be found at:

• http://app.mymaths.co.uk/371-resource/dot-plots

• 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