You will be submitting these data to a test of mean difference between two independent groups such as a T test, or a Mann-Whitney U test. \u00a0The question is, how should you enter these data into the data manager to conduct this sort of analysis?<\/p>\n
Indicator Variable Approach<\/h4>\n
In most professional packages like SPSS, you have to use a grouping or indicator variable — a variable that will tell us which score in our data is from which group.\u00a0 We will call this the “Indicator Variable Approach” to managing our data from independent samples.\u00a0 In Stats Homework<\/em>, we would enter data like this:<\/p>\n Make sure to rename your variables!\u00a0 The guiding philosophy here is that\u00a0all the data\u00a0from one observation or participant is entered into one line — one line per observation.\u00a0 In SPSS, you have to use a numeric indicator variable — e.g., “1” and “2.”\u00a0 In Stats Homework<\/em>, you can use a numeric or non-numeric indicator variable — as long as this variable has two and only two values.\u00a0 So you can use much more descriptive values — “Delayed” and “Immediate.”<\/p>\n If you request a T test for independent samples in Stats Homework<\/em>, you will\u00a0work with a user dialog that looks like this:<\/p>\n You will move the grouping or indicator variable to the blank labeled, “Grouping Variable,” and move the variable with your scores to the blank labeled, “Test Variable.”\u00a0 The values you use for your indicator variable will be used in the output for your analysis.\u00a0 So it’s often best to use descriptive non-numeric values for this variable.<\/p>\n In Stats Homework<\/em>, it is also acceptable to enter the data from two independent samples as two separate variables:<\/p>\n Here, the guiding principle is simplicity — you enter only your data from the study, and\u00a0you\u00a0do not have to create a new variable.\u00a0 In addition, the data layout is visually simple — you can easily see which scores are in which group.<\/p>\n When you request the T test for independent samples, you will see the same dialog as before:<\/p>\n![\"indgroups1\"](\"https:\/\/sites.berry.edu\/vbissonnette\/wp-content\/uploads\/sites\/21\/2016\/06\/indgroups1.png\")
<\/a><\/p>\n<\/a><\/p>\nSeparate Variables Approach<\/h4>\n
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