Chi-square test of independence??

I am running an experiment on aggression. I have a control and an experimental group. I have administered a 29 item 5 point Likert scale to each group. I am interested in their total answers, not each response to the 29 items, just higher values indicating greater aggression. How can I enter this in SPSS and do the chi-square test of independence based on individuals' overall value within each group? Do I create 5 categories such as 1 strongly disagree, 2 disagree, and so forth? Or can I simply make a variable titled "scores" and input each individual's total score and then run the chi-square? I appreciate any help or guidance you can provide.
Also, if I do categorize how do I go about doing so? Is it simply the five items and then the average number of times each participant selected 1, 2, 3...
You create a total score by averaging the 29 items (use MEAN within the
Transform...create new variable window). The you compare this between
groups, using independent samples t-test (comparison of means).
CHI square is useless here, it is for categorical variables.

With kind regards