I am a little stuck on what how to implement and interpret a multiple regression while controlling for age.
I am interested in seeing if there is a positive relationship between depression and use of music for emotional regulation and if this relationship is consistent across adulthood. I have three variables, depression, age and emotional usage of music. All three are continuous data. I have a large data set (2000+) but nearly half the sample are young adults (18-24). There are also very few seniors (65+).
As all the data is continuous and I have two IV's and one DV, multiple regression was the go to. However I am trying to understand how I could make it work and how I could interpret the outcome (I am very new to multiple regression). I have heard that would could hold one variable, like age, constant? How would I do this? Also how much does it matter that younger ages are over represented and the older ages were under represented. Will this bias the data/result?
Any advice would be greatly appreciated!