Including Moderation (interactions) in linear regression using SPSS

In this video, Dewan, one of the Stats@Liverpool tutors at The University of Liverpool, demonstrates how to perform moderations (interactions) as part of a linear regression using SPSS.

[@diyanateoh]

Halo, I’m curious about the main effect of X no need to be consider?

[@cjmt1234]

Thank you for a great video! I have a question: why is it important to centre the variables? Also, in my case, I want to look at the interaction effect of 'Incumbency' on the 'total amount of money' a candidate receives in an election when trying to predict 'vote share (%)' (DV). However, while money is a numerical value, I have coded 'incumbency' as a binary value of either 1 (they are an incumbent) or 0 (they are a challenger, or the seat is uncontested). Can I just multiply these together as you did in the video, even though my variables are different types of data? Thank you for your help!

[@sharons4996]

Thank you!