When an E-Prime experiment terminates without any errors, E-Prime generates data files called edat files. An edat file is created each time the experiment terminates, and each edat file is labeled with the experiment name, subject number, and session number. These files contain the value of each attribute for each trial and log them into a spreadsheet. Depending on how you set up your experiment there can be one or several edat files per subject.
To consolidate the data into a single file, multiple edat files can be merged using a program called E-Merge. E-Merge can merge several edat files together into a single merged file (with the extension .emrg). This file can then be read into another program in the E-Prime suite, E-DataAid. When you open up the Merged file, you will see a large spreadsheet. Each row represents a single trial, or the completion of a procedural object, while the columns store the values of each attribute.
Using E-Merge to consolidate several edat files into one file.
An example screenshot of the E-DataAid interface.
Because every attribute for every trial is logged, and because most experiments contain dozens or hundreds of trials, edat files can become very large. We can reduce the number of visible attributes by applying a filter that only shows the attributes we want to analyze. The analysis can be done with the Analyze tool, which allows you to separate your attributes and subjects into rows and columns and calculate the statistic of a dependent variable.
Steps for analyzing the data in E-DataAid. First click on the "Analyze" button (the one that looks like a calculator). Then filter the trials so that you only have the conditions you wish to analyze. In this example we calculated the mean reaction time to the Stroop stimuli for both the congruent and incongruent conditions for each subject.
Next, click the Run button. You will have one mean reaction time per subject for each condition. These data can then be copied and pasted into a spreadsheet (such as Excel) or exported to a format that can be read by statistical software (e.g., SPSS).
Everything you've learned up to now enables you to create behavioral studies and analyze the data. The next and last tutorial in this series will show you how to adapt this sample experiment for use with an MRI scanner.