All about research methodology

https://www.youtube.com/user/GrahamRGibbs/videos

https://www.youtube.com/watch?v=QFoisfSZs8I

• Type one and Type two errors http://www.stat.nuk.edu.tw/SouthShow.asp?myid=1429

• Extraneous Variable http://www.cs.colostate.edu/~howe/EMAI/ch3/node4.html