Cf Factorial ANOVA Instructions

Two-Way ANOVA Instructions Page 1 of 12

The Factorial ANOVA is a parametric procedure used to determine differences between two or more independent variables (IV), each with two or more levels) on a single dependent variable (DV) For this assignment you are using two IVs or factors so the procedure you will be doing is referred to as a Two-Way Factorial ANOVA. Since we have two levels of one IV and three levels of the other, it can also be referred to as a 2 X 3 ANOVA. This presentation will take you through the steps to run the analysis using SPSS. Step 1: Open the SPSS dataset titled Two-Way Factorial ANOVA Dataset.sav. Before analyzing any of the data, we first want to label some of the variables and levels. This will make the information on the SPSS output much easier to understand. Step 2: Once youve opened the data for this assignment, click on Data and then Define Variable Properties.


Step 3: When the Define Variables Properties box appears, click on time to highlight it and then move it to the Variables to Scan box by clicking the arrow between the two boxes. Do the same with the variable strategy and then click the Continue button.


A new box will appear that allows you to provide a label for the variables you chose. Step 4: Choose the variable time if it isnt already chosen. Click your mouse in the upper right hand box and type in a label for this variable. Since time represents the delay, we will label it Time Delay. Then enter 5 Minutes and 2 Days for levels 1 and 2 respectively.


Click on strategy to change to this variable and repeat the steps to rename the variable and the three levels as shown. Click OK to continue.


A new window will open with text that tells you that you just changed the labels of your variables. Do not close this window since we will need it later but go ahead and return to your original data window. Step 5: We will now run some analyses that are necessary to screen our data and to verify the assumptions of the Factorial ANOVA. These are considered descriptive statistics for the most part so click on Analyze then Descriptive Statistics then Explore.


A new window will open. Since we are now asking SPSS to describe our data, we need to tell it which variables we want to look at and which represent factors (or IVs) and which is our DV. Step 6: Click on Time Delay and then click the arrow to move it to the Factor List. Do the same with Learning Strategy since we are running a two-factor test. Place recall in the Dependent List using the same procedure.


Step 7: Click on Plots in the upper right hand corner of the small window. Then choose the plots and tests that you want SPSS to run. For this assignment, we want to Factor our levels together, draw Histograms of our data, produce Normality plots, and run the Levene statistic using Power estimation. When all of these options are chosen, click Continue. Then click OK to tell SPSS to run the descriptives.


The output window may pop up again to let you know that SPSS is running some new analyses. Since we still need to run the actual Factorial ANOVA though, you need to return to the data window. At this point, the researcher may want to stop running analyses in order to make sure that the quality of the data and the assumptions for the Factorial ANOVA are verified. Recall that if the data quality is poor and/or the assumptions are seriously violated, we cannot proceed with the analysis. Step 8: Click Analyze then General Linear Model then Univariate. This method would have worked for last unit as well although the method we used was somewhat easier than this one.


Step 9: A new window will open asking you to tell SPSS which variables you are analyzing. recall is our DV and Time Delay and Learning Strategies are our Factors or IVs. Place them in the appropriate boxes. Click on Post Hoc on the right hand side of this window.


Step 10: When the new window opens, check the box next to the post hoc analyses you want to run. Again, we chose four of the more common post hoc tests but you only need to choose one. Refer to Chapter 12 in the Howell text for a description of each test and remember to justify your choice when you report the results of this study. Click Continue and then click OK to run the analysis.


Now would be a good time to save both your data and your output. The output window will look very similar to last weeks assignment with a few added charts and graphs since we now have two factors. Writing up the Results: These instructions resulted in the required output to interpret the Factorial ANOVA. It represents the basics of the analysis and interpretation. Be sure to demonstrate your advanced knowledge in your interpretations by incorporating information from your text, supplemental readings, courseroom discussions, and independent study. Also keep in mind that you may not need everything SPSS provides in your output. Take some time to play around with SPSS to see what you can do. When you learn something new, make sure to share it with your classmates. To copy charts and graphs from SPSS for your papers use the Copy Objects command. Make sure that Word is open beforehand so you can Paste the object into your document. When writing a full report, it is best to integrate your graphs and charts into the document and to label them appropriately. Dont forget to SAVE your data, your SPSS output, and your related documents frequently!


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Cf Factorial ANOVA Instructions