I am collecting data from a group of about 189 police officers on a 5-point Likert-Scale (measuring how much the police officers accept rape myths). I have no idea which tests to use to analyse my data. In the end I want to divide the group into male officers versus female officers and compare their acceptance of rape myths to determine if there is a difference between the two groups. I will also gather other geographical data (e.g. years of service), but I have no idea how that can be valuable.
It depends on whether you have a single Likert scale question(which, given your research question, seems unlikely) or multiple scales. If the latter, you then have to decide how you want to combine them.
Although, technically, adding Likert scale questions is invalid (because adding numbers assumes they are at least interval scaled) people do it all the time. It is also possible to do factor analysis of Likert scale items, although some care must be taken. See e.g Joreskog and Sorbom
Other than the likert question, If you have all your variables as categorical e.g. Region(East, West, North, South), Education(Some College, College Degree, Masters Degree, Phd) and so on, you can use MANOVA technique.
"Rape as a myth" as dependent variable. Gender(Male/Female) as fixed factor
Looking at your question, you have "Age" as a continuous variable. you can actually segment age into diffeent defined groups to make it categorical variable and make it useful for MOANOVA. For example you can have age categories as "18 to 25", "26 to 30", "30 to 35" and so on. So now if a respondent stated their age as 23, it will fall under "18 to 25".
This is an youtube SPSS tutorial on how to do MANOVA and how to interpret the output