One Way ANOVA using SPSS
Introduction
The one-way analysis of variance (ANOVA) is used to determine whether there are any significant differences between the means of two or more independent (unrelated) groups (although you tend to only see it used when there are a minimum of three, rather than two groups). For example, you could use a one-way ANOVA to understand whether exam performance differed based on test anxiety levels amongst students, dividing students into three independent groups (e.g., low, medium and high-stressed students). It is important to realise that the one-way ANOVA is an omnibus test statistic and cannot tell you which specific groups were significantly different from each other; it only tells you that at least two groups were different. Since you may have three, four, five or more groups in your study design, determining which of these groups differ from each other is important. You can do this using a post-hoc test (N.B., we discuss post-hoc tests later in this guide)
Example
A manager wants to raise the productivity at his company by increasing the speed at which his employees can use a particular spreadsheet program. As he does not have the skills in-house, he employs an external agency which provides training in this spreadsheet program. They offer 3 courses: a beginner, intermediate and advanced course. He is unsure which course is needed for the type of work they do at his company, so he sends 10 employees on the beginner course, 10 on the intermediate and 10 on the advanced course. When they all return from the training, he gives them a problem to solve using the spreadsheet program, and times how long it takes them to complete the problem. He then compares the three courses (beginner, intermediate, advanced) to see if there are any differences in the average time it took to complete the problem.

Setup in SPSS
In SPSS, we separated the groups for analysis by creating a grouping variable called Course (i.e., the independent variable), and gave the beginners course a value of "1", the intermediate course a value of "2" and the advanced course a value of "3". Time to complete the set problem was entered under the variable name Time (i.e., the dependent variable). In our enhanced one-way ANOVA guide, we show you how to correctly enter data in SPSS to run a one-way ANOVA (see here). You can learn about our enhanced data setup content in generalhere. Alternately, we have a generic, "quick start" guide to show you how to enter data into SPSS, available here.
Test Procedure in SPSS
The eight steps below show you how to analyse your data using a one-way ANOVA in SPSS when the six assumptions in the previous section,Assumptions, have not been violated. At the end of these eight steps, we show you how to interpret the results from this test. If you are looking for help to make sure your data meets assumptions #4, #5 and #6, which are required when using a one-way ANOVA, and can be tested using SPSS, you can learn more here. * Click Analyze > Compare Means > One-Way ANOVA... on the top menu as shown below.

* You will be presented with the following screen * Transfer the dependent variable (Time) into the Dependent List: box and the independent variable (Course) into the Factor: box using the appropriate buttons (or drag-and-drop the variables into the boxes), as indicted in the diagram below:

* Click the button. Tick the Tukey checkbox as shown below:

* Click the button. * Click the button. Tick the Descriptive checkbox in the –Statistics– area, as shown below:

REFERENCE: https://statistics.laerd.com/spss-tutorials/one-way-anova-using-spss-statistics.php Leard Statistics