@book{140662,
	author = {Christensen, Howard B. and Brigham Young University, Provo, Utah.},
	title = {Statistics step by step},
	publisher = {Houghton Mifflin},
	year = {c1977.},
	address = {Boston},
	note = {Prelim. ed. published in 1974 under title: Introductory statistics.}
}