Homework Correction

Q2 Pg 356

i. 25ii. 10iii. 3

Pie Charts and Histograms

What we did last week…

• Created Tally Tables

• Created Frequency Tables

• Drew Bar Charts and Line plots

Today we will…

1. Create Pie charts from Data

2. Analyze Pie charts

3. Create Histograms from frequency Table

4. Analyze Histograms

Pie Charts

Pie Charts

Why use a pie chart to represent data?• A pie chart is a good way of displaying data

when you want to show how something is shared or divided

They are very useful to display categorical data

Pie Charts

Train; 24

Coach ; 12

Car; 59

Ship; 11

Plane; 14

Mode of Travel

A Pie Chart is divided into

sectors

The Whole circle represents all the people surveyed

The Angle of each sector is

proportional to the frequency for that

category

How do we draw a pie chart?

You will need1. Pencil2. Protractor3. Ruler

Step 1

Tabulate your data:

Type of Transport Frequency Calculation

Train 24

Coach 12

Car 59

Ship 11

Plane 14

Total 120

Step 2

Calculate the angle needed for each category:

We do this by using a simple formula

Complete Table

Type of Transport

Frequency Calculation

Train 24 24/120 x 360° = 72°Coach 12 12/120 x 360° = 36°

Car 59 59/120 x 360° = 177°Ship 11 11/120 x 360° = 33°

Plane 14 14/120 x 360° = 42°

Total 120 360°

Now draw!

1. Draw a Circle using compass

Now Draw!

2. Measure out each angle using your protractor

Now draw!

3. Draw lines where appropriate and you're done!

Train; 24

Coach ; 12

Car; 59

Ship; 11

Plane; 14

Mode of Travel

Objective Check

1. Create Pie charts from Data

2. Analyze Pie charts

3. Create Histograms from frequency Table

4. Analyze Histograms

Analyzing Pie Charts

This is the most important aspect of reading pie charts

What is the use in seeing something if we cannot understand it?

Analyzing Pie Charts

Once given certain parts of information we can work backwards to calculate something that

may be missing

Example

Objective Check

1. Create Pie charts from Data

2. Analyze Pie charts

3. Create Histograms from frequency Table

4. Analyze Histograms

Histograms

Histograms are one of the most common ways to represent data

Histograms are similar to bar charts but here are some differences:• There are no gaps between bars in a histogram• They are used to show continuous data• The data is always grouped

Histograms

ExampleTime (s) 0 - 10 10 - 20 20 – 30 30 - 40 40 - 50 50 - 60

No of Students 1 2 8 11 6 3

Objective Check

1. Create Pie charts from Data

2. Analyze Pie charts

3. Create Histograms from frequency Table

4. Analyze Histograms

Interpreting Histograms

Similar to bar charts, simply read off any data needed

Try for yourself Question 1 Page 361

Objective Check

1. Create Pie charts from Data

2. Analyze Pie charts

3. Create Histograms from frequency Table

4. Analyze Histograms

Homework

Page 359 Q 10, 12

Page 362 Q 5

Next week…

We will start looking at the spread of data