Supplementary Materials for Chapter 15 - Analysing Data

Transcription

1 Supplementary Materials for Chapter 15 - Introduction Analysing Data This resource supplements the discussions in Chapter 15 of the book - Analysing Data (pp ) under the heading Analysis of Quantitative Data. This online segment was required because Figures 15.1 to had to be excluded from the book due to technical reasons. This topic area in the Online Resource Centre will address the following: The manual method of analysing quantitative data Analysis of quantitative data using Excel computer software Analysis of quantitative data using SPSS software

2 The Manual Method of Analysing Quantitative Data If the source of quantaitive data comes from less than 200 surveys or units of analysis (texts) content analysed, and you are not familair with the use of the relevant computer software such as SPSS or Excel, the data analysis may be carried out manually without much difficulty using pen and paper. You will need an unused or blank survey or conent analysis coding sheet when manually coding the data and use a slash (/) near the category of each variable on the blank survey or coding sheet where a response has been recorded to indicate it as been selected by the respondent (in a survey) or coder (in a content analysis). As you code each survey or coding sheet, you can indicate the selection as /, //, ///, ////, and //// to indcate that 1, 2, 3, 4 and 5 occurences have been recorded respectively. Remember to count incidents where there has been no response to each variable or question so that the frequencies and percentages can be calcualted accurately. Once the data entry for all the surveys or coding sheets have been completed, add up the slashes under each category (e.g. //// //// /// as 13) to indicate their frequencies (how many per category of the same variable) and calcualte their percentages. You can also calculate the mean, medium, mode, maximum, minimum, and range the same way. However, if you need to calcualte the cross tabulations to compare between variables and their categories (e.g. Numbers and percentages of Readers of Newspaper A and B who are male and female) it may be more complicated and may require using software such as Excel. Analysis of Quantitative Data Using Excel Computer Software Excel and SPSS (Statistical Packages for the Social Sciences) are the most commonly used computer software in the analysis of quantitative data in the discipline of media and communication. Data analysis using Excel: Today, most computers will include Excel software as a matter of course, which means learning to carry out statistical analysis using it will be accessible to you than learning SPSS. A manual for using Excel accompanied by a CD- ROM (e.g. Rosenberg, 2007) will help you to learn and carryout a descriptive data analysis and the statistical tests discussed in the book under Chapter 7- Measurements. A row in an Excel data file will be dedicated to one survey or case or unit of analysis (coding sheet) while each column will be devoted to one variable (e.g. sex, age group etc.). You may be able to follow the Excel tutorial from Rosenberg (2007) to teach yourself how to do it. Many universities and other organisations conduct regular Excel workshops for their staff and other members such as students. So keep an eye out for them. Also note that Excel data files can be transferred to SPSS for analysis, if you or another person would like to use the SPSS software to analyse the data at a later time. References Rosenberg, K M The Excel statistics companion-cd ROM and manual. Thomson- Wadsworth, Belmont, CA.

3 Analysis of quantitative data using SPSS software Creating a data file Once you open the SPSS program on your computer assuming it has been downloaded from your organisation s website (which has a site licence) onto your desktop open its data entry window. This will look similar to a blank data file in Excel. On the top row, columns are labelled var while rows are numbered from 1 onwards. Figure 15.1 SPSS data entry window Note that just as with Excel, each row in SPSS is devoted to each case (survey or content analysis coding sheet) and each column is devoted to one variable in the survey or coding sheet. Move the cursor to the first cell on the top left-hand corner of the data file and click it. Pull down the Data menu to open the dialogue box titled Define Variable. This is where you name each variable for your data file. Each name or value can take up to eight characters and can be numeric (numbers), a date ( ) or a string (words or phrases).

4 Figure 15.2 Define Variable dialogue box You will see that the Define Variable dialogue has the Variable Name VAR0001 (eight characters), which can be changed to any variable name of your choice. Let us say it is a name of a newspaper. So the variable can be named NEWSPAPR. Click OK and you will see the dialogue box Define Variable Type.

5 Figure 15.3 Define Variable Type dialogue box You will need to select the type of variable from the list (numeric, date, string, dollar etc) and indicate the width of the variable (up to eight spaces) and the number of decimal places needed to code your data if it is a numerical value (for example, two decimals). Click Continue to open the Define Labels dialogue box.

6 Figure 15.4 Define Labels dialogue box When it asks for Variable Label, we can indicate Newspaper. It is a good idea to use variable names that are easily linked to the actual variable to make the analysis and interpretation of data analysis easier to grasp. In other words, it is better to use NEWSPAPR than labelling your variables VAR 1, VAR 2 etc. This dialogue box also asks for values (or categories of the variable). Looking at your survey or the content analysis coding sheet, you could list Value 1 for the Value Label MelbAge (The Age Melbourne). Click Add and enter the next one: Value 2 as AUSTRALN (the Australian newspaper). Click add again and continue until all the values for the variable have been entered. When it is done, click Continue. Enter the next variable until completed. Make sure you choose the correct variable type for each variable and remember to save your data file. Entering the data or coding Take each survey (or content analysis coding sheet) and enter the corresponding data under each variable. Once all data have been entered, save the file. Now you are ready to carry out your data analysis.

7 Analysing the data Examine the research questions (or hypotheses) to identify the independent and dependent variables involved and what types of statistical analyses are required to examine or test them. Identify the variables that need to be selected for calculating descriptive statistics, such as frequencies and statistics. Select the Frequencies dialogue box for this purpose. Figure 15.5: Frequencies dialogue box Note that the list of your variables will appear on the left-hand side, from which you need to select the ones needed for the calculations. You will also be able to obtain the descriptive summaries for mean, median, mode, maximum, minimum and range. Click the appropriate boxes such as Display Frequency Tables and select the statistical tests you want and click OK. This will provide you with your output tables that may be used as tables in your report. You may carry out Cross tabs (cross tabulations) the same way.

8 Figure 15.6 Output window for Frequencies