@book{115421,
	author = {Healey, Joseph F., and Healey, Joseph F.,},
	title = {The essentials of statistics :},
	publisher = {Thomson/Wadsworth,},
	year = {c2007.},
	address = {Belmont, CA :},
	note = {Abbreviated version of: Statistics : a tool for social research.},
	url = {http://www.loc.gov/catdir/enhancements/fy1515/2006904375-b.html}
}