Hello, I am writing thesis at the moment and have a question.

I want to run multiple regression analysis to examine relationship between 5 independent variables and 1 dependent variable.

Each independent variable is composed of 3~5 questions.

Can I just add up each value or question instead of averaging them?

Since each independent has different number of items and each item is Likert scale, the range of added up score differs as 3~15, 4~20, 5~25.

Would it cause a big problem on running multiple regression and should I always use mean value?

Thanks in advance.