https://www.youtube.com/watch?v=ObEYldr3dmo
https://www.youtube.com/watch?v=v0oz_K-GdgQ
May Allah grant rahmah for his Soul ..Sir Abdul Halim Abdul Hamid
Correlation Coefficient Degree of freedom (checking validity)
https://www.youtube.com/watch?v=gVUR7sR2iDM
https://www.spsstests.com/2015/02/how-to-test-validity-questionnaire.html
http://site.iugaza.edu.ps/nbarakat/files/2010/02/correlation-table-pearson.pdf