Table 4.

Comparison of Scientific Yield and Costs of Three Experimental Design Alternatives

	Individual experiments	Complete factorial design	Fractional factorial design (half fraction)
Interaction effects	Cannot be estimated	All can be estimated	Two-way interactions can be estimated
Number of experimental conditions	10	32	16
Experimental condition costs @ $2,000/condition	$20,000	$64,000	$32,000
Number of subjects	2,525	505	505
Subject costs @ $100/subject	$252,500	$50,500	$50,500
Total costs	$272,500	$114,500	$82,500