ANOVA with Excel
This exercise is designed to show you how complete a two-way ANOVA by computer. You may either use SPSS or Excel. If you wish to conduct this analysis by use of SPSS, go to the Web page, ANOVA with SPSS.
As a preliminary step, you must secure the proper file for data analysis. These files are available from the Data Sets Web page. In particular, if you have not already done so, you need to download the file "FALANOVA.XLS".
Some background on this assignment may help. It involves the study of the impact of fallacious arguments on attitudes. You already probably verified the reliability of the attitude measure by completing an exercise for Chapter 8 and, if you have completed the computer assignments for each chapter, you have computed a t test with this dependent variable as part of an exercise in Chapter 13. The dependent variable is attitude toward the topic (as created in chapter 8). The study now has two independent variables. The first independent variable is a true experimental variable: the use or non-use of the non sequitur fallacy in a persuasive message. The second independent variable is a moderator variable: sex of the respondent. This second independent variable is a moderator variable and, of course, it is not experimentally manipulated. Thus, each independent variable has two levels. The experimental variable dealing with the use of the non sequitur fallacy is identified as "falexper" (1= with the fallacy presented to subjects; 2=without the fallacy presented to subjects). The remaining (moderator) independent variable is "sex" and is identified with 1 equal to males and 2 equal to females. Because the researcher is interested in examining any main an interactions a 2 x 2 factorial analysis of variance is the chosen variable of interest. Simple defaults of alpha risk of .05 are applied in this exercise.
|Start Excel and from the "File" menu "Open" FALANOVA.XLS (if you have not already done so).|
Excel places some limitations on format for inputting data for two-factor analysis of variance. First, one must have equal numbers of events in the cells of the factorial design. Second, the levels of one independent variable must be in separate columns of the spreadsheet. Third, the cell entries must be placed in the cells created by this arrangement--they cannot be placed in a separate column. To avoid the potential frustration involved in modifying the data set, the data set has already been modified for you.
|With the spreadsheet before you, locate a place to put the output. In this case, go to row 2 column E and click on the cell to make it active. Click on the "Tools" menu and then click on "Data Analysis." In the "Data Analysis" dialog box select "Anova Two-Factor With Replication" and click on 'OK."|
In the dialog box "Anova: Two-Factor With Replication" go to the "Input Range:" field and enter the starting cell and ending cell for the entire matrix (in this case, $A$1:$C$17). For the "Rows per sample:" field, enter the number of events in each condition (8 in this case, following random deletion of items to produce equal cell sizes).
Click on the "Output Range:" button, and enter the target cell in the field where you wish the output to be placed ($E$2). Click "OK."