Bar Graphs

Look at the way a bar chart is constructed Look at the way a bar chart is constructed. Can you name its different parts? What goes here? What is this called? What is this? What do we call this?

A bar chart always has a title. Vertical axis (y). Always labelled and numbered. The height of the bars show how many of something was scored/recorded. Horizontal axis (x). Always labelled.

Can you read the answers? What does this bar chart show? How many children were surveyed? Which is the favourite flavour? Which is the least liked? What intervals are used on the y axis? What intervals could you use if twice as many children were surveyed? Can you read the answers? Favourite Crisps 8 7 6 5 Number of children 4 3 2 1 Salt and vinegar Cheese and onion Prawn cocktail Ready salted Bacon Worcester sauce Barbeque Flavours

Types of Bar Graphs VERTICAL Graph 1.1 A bar graph is used to show relationships between groups. The two items being compared do not need to affect each other. It is a fast way to show big differences. Items can be represented in horizontal bars or in vertical columns. Look at the following graph which shows the data using horizontal bars. Carefully read the title and the labels on each axis to see what data is displayed by the graph. Which food has the highest percent of sugar? Chocolate Bar Which food has the lowest percent of sugar? Ketchup

Types of Bar Graphs H O R I Z O N T A L Graph 1.2 What is the most favored after school activity? Visit with Friends What is the least favored after school activity? School Clubs H O R I Z O N T A L

Types of Bar Graphs SINGLE BAR GRAPHS Graph 1.3 What two countries have the highest rate of unemployment? Finland and Sweden Which country has the lowest rate of unemployment? Norway If Finland’s population is 5.4 million people, how many are unemployed? 329,400 SINGLE BAR GRAPHS

Types of Bar Graphs DOUBLE BAR GRAPHS Graph 1.4 Which countries do men have a higher rate of unemployment? Iceland and Norway DOUBLE BAR GRAPHS

The table shows the highway speed limits on interstate roads The table shows the highway speed limits on interstate roads .within three states Rural Urban State 70 mi/h 65mi/h Florida Texas 65 mi/h 55mi/h Vermont

Step 1 Choose a scale and interval for the vertical axis. Rural Urban State 70 mi/h 65mi/h Florida Texas 65 mi/h 55mi/h Vermont

Step 2 Draw a pair of bars for each state’s data. Use different colors to show urban and rural. Rural Urban State 70 mi/h 65mi/h Florida Texas 65 mi/h 55mi/h Vermont

Step 3 and 4 Label the axes and give the graph a title. Speed Limit on Interstate Roads Label the axes and give the graph a title. Make a key to show what each bar represents Urban Rural Speed Limit (mi/h)

Types of Bar Graphs STACKED BAR GRAPHS Graph 1.5 How many cups of coffee were sold in January? 40 How many cups of coffee were sold downtown in February? Approx. 26 How many cups of coffee were sold at the mall in February? Approx. 42 What fraction of coffee that was sold in April was sold downtown? Approx. 2/3 What month were more cups of coffee sold downtown than at the mall? April What percent of coffee was sold at the mall in May? Acceptable answers between 30-40% What was the percent increase in cups of coffee sold from January to February? Acceptable answers between 65-70% What is the ratio of coffee sold in March to the amount sold in May? Approx. 5:3 STACKED BAR GRAPHS

How can you collect the information needed to construct a bar chart? By making a tally chart first!

Flavour Tally Salt and vinegar Sour Cream and Onion Ketchup Plain Dill Pickle BBQ Insert any other flavours here

Create a Tally Chart with Chip Flavours Go around the class and ask the favourite flavour Construct a Bar Graph with the information Be sure to label your axes correctly and give your graph a title With support