## Levels of Measurement

There are many different methods for analyzing quantitative data; each method is dependent on the type of data gathered as well as the research question being addressed. The first step in analyzing data is to determine what kind of data you have—the level of measurement. Determining the level of measurement is a method of classifying the variables within a research study. Classifying a variable into its appropriate level of measurement helps a researcher determine the most appropriate statistical analysis for those data and to interpret the data the variable generates.

In this Discussion, you identify independent and dependent variables in your research problem, which you identified in the Week 2 Discussion. You classify these variables into their appropriate levels of measurement and determine suitable ways of analyzing the data generated by each variable.

To prepare:

Review the materials presented in Chapter 1 of the Polit textbook.

Consider Dr. Pothoff’s comments in this week’s media presentation on data analysis.

Recall your research problem statement developed for the Week 2 Discussion. Based on your problem statement, develop a research question to address the problem.

Ask yourself:

Do the research question involve a comparison of groups or the relationship of variables?

How many independent variables do I have? Dependent variables? What are they?

Is the independent variable categorical or continuous?

Is the dependent variable categorical or continuous?

What might be the advantages, or disadvantages, of each variable’s level of measurement?

Post by Day 4 a cohesive summary of the following:

Post your research question. Describe the independent and dependent variables.

Identify the level of measurement of both the independent and dependent variables. Provide a brief rationale for your classification of each variable.

Discuss considerations of analyzing data related to each variable based on its level of measurement. Identify any advantages or challenges you might encounter in your statistical analysis of each variable.

Readings

Course Text: The Practice of Nursing Research: Appraisal, Synthesis, and Generation of Evidence

Chapter 21, “Introduction to Statistical Analysis”

This chapter discusses the concepts of statistical analysis with regard to hypothesis testing. The chapter also identifies and defines common statistical terminology.

Course Text: Polit, D. (2010). Statistics and data analysis for nursing research (2nd ed.). Upper Saddle River, NJ: Pearson Education Inc.

Chapter 1, “Introduction to Data Analysis in an Evidence-Based Practice Environment”

This chapter provides an introduction to quantitative and qualitative data in evidence-based practice. The chapter introduces levels of measurement and types of statistical analyses relevant to different types of research studies.

Chapter 2, “Frequency Distributions: Tabulating and Displaying Data”

Chapter 2 discusses frequency distributions as well as the different methods of presenting data, especially when data are very extensive. The chapter includes information on the use of bar charts, pie charts, histograms, and frequency polygons.

Chapter 3, “Central Tendency, Variability, and Relative Standing”

This chapter examines the many ways data distribution for a quantitative variable can be described through shape, central tendency, and variability.

Software

IBM SPSS Statistics Standard GradPack (current version). Available in Windows and Macintosh versions. Please refer to the IBM SPSS Software area on the left navigation bar for more information on how to install, register, and license this software

Optional Resources

Article: Bilheimer, L. T., & Klein, R. J. (2010). Data and measurement issues in the analysis of health disparities. Health Services Research, 45(5), 1489–1507. doi:10.1111/j.1475-6773.2010.01143.x

Retrieved from the Walden Library databases.

Article: Granberg-Rademacker, J. S. (2010). An algorithm for converting ordinal scale measurement data to interval/ratio scale. Educational & Psychological Measurement, 70(1), 74-90.

Retrieved from the Walden Library databases.

Website: Statistics Help for Students. (2008). Retrieved from http://statistics-help-for-students.com/

This site provides step-by-step procedures and screenshots for working with SPSS.

Tutorial: Walden University. (n.d.). Descriptive statistics. Retrieved August 1, 2011, from http://streaming.waldenu.edu/hdp/researchtutorials/educ8106_player/educ8106_descriptive_stats.html