1 answer
(click or scroll down)
Human brains vary slightly in size. Most sources put the average brain in a range, rather than a specific weight or volume.
Check these sites.
http://hypertextbook.com/facts/2003/RachelScottRosenbluth.shtml
http://www.wsu.edu:8001/vwsu/gened/learn-modules/top_longfor/phychar/culture-humans-2two.html
http://serendip.brynmawr.edu/bb/neuro/neuro02/web2/tvaughan.html