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Chapter 17: Conducting Univariate Analyses Frequency distributions The first step in analysis is to analyze data for each of your key variables Analysis of one variable at a time is known as univariate analysis. This is done by first developing a frequency distribution of the attributes for each variable. A frequency distribution, also referred to simply as a distribution, describes how many times each attribute of a variable occurred. Distributions can be generated by hand tallying or by using statistical analysis software on a computer. We will use hand tallying to show how distributions are created. (The computer essentially does the same thing and presents the results on a monitor or as a print out). Hand tallying, however, is practical only when you have a small sample. With large samples, computer analysis is the only practical way to go. Tallying involving categories The way data are tallied depends upon the level of m easurement used. Different procedures are used for data in the form of categories in contrast to numerical data. Variables represented by categories are measured at the nominal or ordinal level. Tallying responses for these items simply requires counting how many times each response category was chosen for each item. Following is an example of a nominal item used in a survey among villagers in central Sudan:
A tally sheet, such as Table 17.1, can be used in tallying responses to an item. Our sheet shows the number of the item from the questionnaire (which, in our example, happened to be 11) and the four responses for this item. We listed a shortened version of the responses, although codes (1 through 4) could have been used as well. Using codes is simpler, but can lead to mistakes in coding. Using the verbal form generally results in fewer errors in recording responses for getting a tally. We also included a category labeled "other" to record any unexpected responses. Using the tally sheet, we place a tally mark (/) following each response code for each time each appears. Tallies are grouped in sets of five to aid in counting. Tally marks are then added to get the frequency for the number of times each response category was selected. The letter "f" is sometimes used for frequency in the headings of tables. Frequencies for each of the responses are recorded and added to get the total for the analysis. In research, the total for an analysis is called the "N" for the number of responses for an analysis. As a rule, the N for an analysis should equal the N for the sample. This is why we added the "no data" category. |