Compare mean effect of one predictor based on another predictor I would like to compare the effect of one IV ("sensation seeking") on a DV ("intended infidelity") based on another IV ("gender"). Actually I really just want to compare the means. So I would like to compare the mean effect of sensation seeking (a continuous variable with 5 levels) for males and females on intended infidelity (a continuous variable with 4 levels). Why can't I seem to do this in SPSS? Do I have to do a moderation analysis? Can I re-compute the variables and into what? Thanks very much for any suggestions! 
 A: it sounds like you might want a simple linear regression to start, and then a regular linear regression when you add the gender variable.  i believe the spss path to that would be analyze > regression > linear.  if you only use one IV - sensation seeking - at first, that will tell you the linear relationship between that and intended infidelity.  it will act just like that y = mx + b equation of a line from high school.  you add that these are continuous variables in four levels: unless you have a good reason, use all the information you have and analyze them as continuous variables  :)
after that, you can go back and add the male/female variable to your model to view how much of an effect gender has compared to sensation seeking.  i'd recommend you re-compute your male/female variable to a column of all zeroes and ones, instead of ones and twos.  this will make it easier for you to interpret the results.  at the point you've added this second variable, your equation will expand to y = nw + mx + b
