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Image of a researcher AEE 578--Scientific Inquiry in Agricultural and Extension Education
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Variables, Hypotheses and Scales of Measurement
Introduction:

Image of a magnifying glass 		It has been said that English is a difficult language to learn because one word can have several meanings. This is also a problem in research. We routinely use the term "variables" and "hypotheses" in discussing research. However there are different types of variables and different types of hypotheses. Before one can truly understand the research process, it is critical that one understand the concept of "variables" and "hypotheses" and be able to identify the different categories of variables and hypotheses. So you need to fasten your seatbelt and concentrate on the information about variables and hypotheses presented in this lesson. This is foundational information that you need to master.
Learning Objectives:

Icon of a signpost 		image of a ball Define what is meant by the term "variable"
image of a ball Distinguish between independent, dependent, moderator and extraneous variables
image of a ball Classify data as being nominal, ordinal, interval and ratio.
image of a ball Define hypothesis
image of a ball Differentiate between directional and nondirectional hypotheses
 
Instructional
Activities:

Icon of a computer 		image of a ball Read Chapter 3 " Variables and Hypotheses" in the course text, How to Design and Evaluate Research in Education (Fraenkel & Wallen).

Image of a blue ball View a YouTube video that looks at independent and dependent variables

image of a ball See the examples of independent and dependent variables at Connexions.

image of a ball See some more examples that distinguish between independent and dependent variables.

image of a ball And one more example that looks at independent and dependent variables.

image of a ball The University of New England (Australia) has a pretty nice discussion of independent and dependent variables.

image of a ball And this is the last example of independent and dependent variables. After reading the chapter in the book, viewing the powerpoint and checking out these links, you should be able to identify independent and dependent variables.

image of a ball In conducting research one needs to be able to classify the data collected. The book uses the terms "quantitative variables" and "categorical variables" This is a slight oversimplification. There are actually four categories of data (or variables) - nominal, ordinal, interval and ratio. Nominal and ordinal data could be classified as categorical data while interval and ratio is definitely quantitative data. When one analyzes data, these distinctions become very important. And it helpful to be aware of the categories in classifying the types of research being conducted. Read Trochim's definition of each type of variable.

image of a ball Cliff's Notes has a nice concise description of the various levels of measurement.

image of a ball The ALLPSYCH website has a nice table that looks at the scales of measurement.

image of a ball If you need additional help in figuring out how to classify data, here are two videos. The first video is really about how to use Excel to make pivot tables but if you can wade through the extraneous information the presenter does explain nominal, ordinal, interval and ratio data. The 2nd video is rather amateurish but the "headless professor" does explain the four levels or scales of measurement.

image of a ball Read this discussion of research hypotheses from the University of New England.

image of a ball View this lesson on how to write a hypothesis.

image of a ball See what Dr. Ricks says about writing hypotheses.

image of a ball  At one time we used Trochim's Research Methods Knowledge Base as the text for this class. See what he says about Hypotheses.

image of a ball This youtube video explains the difference between a theory and a hypothesis.

image of a ball View the PowerPoint presentation on Variables, Hypotheses and Measurement Scales
Review:

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 Image of a blue ball  The publisher of the textbook has some excellent information to support the text; you should check it out:
 Image of a blue ball Visit the text site and complete the multiple choice questions for Chapter 3

Additional Resources:
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 		Image of a blue ball IF you want to see more (NOT required):
Assignments:               
Icon of note pad 		   Image of a blue ball Complete the variables, scales and hypothesis worksheet.

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