homework correction q2 pg 356 i.25 ii.10 iii.3. pie charts and histograms
TRANSCRIPT
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