In this section, we will see how data is collected and organised, using a tally chart, and displayed using
A hypothesis is an idea that you want to investigate to see if it is true or false. For example, you might think that most people in your school get there by bus. You could investigate this using a survey. A tally chart can be used to record your data.
We can also see that the most common way of getting to school is by bus, because it has the highest frequency. The category or value with the highest frequency is known as the modal class or mode.
We can illustrate the data in the table above using:
Note how a half-person picture is used to represent one person.
(2) Bar Chart
Note how the height of the bar represents the frequency; each section represents one person.
(3) Pie Chart
A pie chart uses a circle divided into several pieces of pie or sectors to represent
each of the frequencies.|
The first step is to work out what angle in the circle will represent one person.
There are 360º in a full circle and 30 pupils in this survey, so:
The completed calculations for this are shown in the table below.
It is important to always check that the angles add up to 360º. If they don't add up to 360º, then you have made a mistake.
The completed pie chart looks like this:
You should always label each sector of the pie chart with a name and an angle.
When plotting a bar chart, simply click a point on the grid and a bar will appear leading up to that point.
Click on a different point in the same column and the bar will change height.
The children in a class were asked to state their favourite crisps. The results are given in the chart below.
The pictogram below illustrates the ages of some children who belong to a junior tennis club.
The bar chart below gives information about the pets owned by the children who live in a particular road.
Malcolm thinks that the dice in his Monopoly set is unfair because he never gets a 6 when he wants one.
He decides to test the dice and rolls it 60 times. The picture below shows his results.
Enter the data in the bar chart on the right. You could either make up a tally table to find the frequencies or you could attempt to add the data into the chart directly.