Sumber

1. www.wikipedia.com
2. http://matematika-ipa.com/statistika-diagram-batang-diagram-garis-mean-median-modus-matematika/
3. http://skripsimahasiswa.blogspot.com/2010/09/ukuran-pemusatan-data-central-tendency.html
4. https://www.google.co.id/imghp?hl=en&tab=wi
5. http://oelatbarca.blogspot.com/2011/11/tendensi-sentral.html
6. www.google.com
7. dan lainnya :)