1. Lecture five and six Graphical Representation of Data
Basic Statistics
Lecture five and six
Graphical Representation of Data

2. Bar Graph
A bar graph is a graph that uses separated bars to represent frequencies. Bar graphs are used to organise and present data that ate categorical. The bar do not touch each other.

3. Histogram
A histogram is a graph that uses bars to represent frequencies; the bars touch.

4. Line Graph
Line graphs are used to show trends in data at equal intervals.

5. Pie Chart
A pie chart is a graphic representation of the proportion ( or percentage ) of each category set of data. They have great visual impact and are commonly used in newspapers and magazines.

6. Stem and Leaf Diagram
Stem and leaf retains data in its original form by providing a visual representation.
For example, let us construct a stem and leaf diagram for the following Reading scores.
80, 85, 110, 95, 95,100,45, 95, 130,75,80,100,120,110,125,75,100,40,75,110,150

7. steps Split the data into two pieces the stem and leaf
Arrange the stems from low to high
The leaves on the right should be in order of magnitude.
No commas should appear on the right
There should be at least five but no more than twenty rows.

8. To Recap the data presented are as follows: 80, 85, 110, 95, 95,100,45, 95, 130,75,80,100,120,110,125,75,100,40,75,110,150 Stem and Leaf Diagram 5 6
8 0005
9 5555
10 000
11 000
12 05
13 0 14
15 0

9. The dependent variable is always assigned to the y-axis.
Graphing
In graphs, the axis of the variables are assigned, then scales and labels are added.
The dependent variable
is always assigned to the y-axis.
relies on the changes in the independent variable (reaction).
is what we measure.
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The independent variable
is always assigned to the x-axis
does not rely on an other variable (action).
values can be chosen freely.