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

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.

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

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

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.

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

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.

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 4 0 5 5 6 7 05555 8 0005 9 5555 10 000 11 000 12 05 13 0 14 15 0

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. | | | | | | |________________________________   The independent variable is always assigned to the x-axis does not rely on an other variable (action). values can be chosen freely.