Ch. 1. Regression with SPSS
Ch. 7. Regression with SPSS
http://psych.unl.edu/psycrs/statpage/quantint.pdf
http://quantpsy.org/interact/interactions.htm
http://essedunet.nsd.uib.no/cms/topics/regression/7/2.html
https://www.youtube.com/watch?v=l3Aoikhaxtg
https://www.youtube.com/watch?v=aeT8MkG3bx8
https://www.youtube.com/watch?v=aVV7KnAr-qY
https://www.youtube.com/watch?v=vYsjJpyrHFc
https://www.youtube.com/watch?v=SdOrkPn7d8Y
https://statistics.laerd.com/spss-tutorials/ancova-using-spss-statistics.php