Qualitative Research Methods: Statistics & Graphical TechniquesBy

Jayadeva de Silva

Often in research, large amounts of data are collected Statistics and data analysis procedures generally yield their output in numeric or tabular form, graphical techniques allow such results to be displayed in some sort of pictorial form.

Students engaged in research work are expected to be able to use the following in presentation of their data

Bar chartHistogramLine graph

Frequency polygon

The choice of appropriate statistical graphics can provide a convincing means of communicating the underlying message that is present in the data to others.

Graphical statistical methods have four objectives:

The exploration of the content of a data set The use to find structure in data

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Checking assumptions in statistical models Communicate the results of an analysis.

If one is not using statistical graphics, then one is forfeiting insight into one or more aspects of the underlying structure of the data.

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What is a Bar Chart?

A bar chart shows how frequently a particular category of data occurs by representing the data using a series of discrete (separate) bars next to, but not touching one another.Bar charts are commonly used to represent data that have discrete categories such as age groups and sex.

What is a Histogram?

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A histogram, or graph of a frequency distribution, is made by labelling class intervals on the horizontal ( x ) axis, and frequencies the number of scores in each class) on the vertical ( y ) axis.Next, bars are drawn for each class interval, with the height of each bar determined by the number of scores in each class.

What is a Line Graph

A line graph is a pictorial representation that indicates the relationship between two factors, or two variables in an experiment.

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The horizontal, or X, axis usually has the independent variable plotted on it, while the vertical, or Y, axis usually has the dependent variable plotted along it.

What is a Frequency Polygon?

A frequency polygon is a graph of a frequency distribution in which the number of scores falling in each class is plotted as points, with a line being drawn to connect the points.

What is a Frequency Distribution?

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A frequency distribution is a table wherein an entire range of scores is divided into a series of equally sized increments (or class intervals), with the number of scores that fall into each class recorded.

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