Inferences we make about underlying cognitive processes can be jeopardized in two ways due to problematic forms of aggregation. First, averaging across individuals is typically considered a very useful tool for removing random variability. The threat is that averaging across subjects leads to averaging across different cognitive strategies, thus harming our inferences. The second threat comes f...

Factorial experiments are widely used in industrial experimentation and other fields. Whenever a factorial experiment is not designed as a full factorial but as a – regular or non-regular – fraction thereof, choice between competing designs and interpretation of experimental results should take into consideration how the experimental plan will confound experimental effects. This article propose...

k 2 full factorial designs may be prohibitively expensive when the number of factors k is large. The most popular technique developed to reduce the number of treatment combinations is the fractional factorial design; confounding in estimating the model parameters naturally results in various resolution and aberration levels. While very useful, these resolution levels may not satisfy experimente...

We examined effects of feeding chicks differing levels of macronutrients on performance during the first 7 d posthatch in this study. Four experiments were conducted using male Ross x Ross broiler chicks. The first experiment examined, in a 3 x 3 factorial design, the effect of feeding fat at 3, 7, and 11% and protein at 18, 23, and 28%. With increasing protein and fat levels feed intake and BW...

Herpes simplex virus type 1 (HSV-1) is known to cause diseases of various severities. There is increasing interest to find drug combinations to treat HSV-1 by reducing drug resistance and cytotoxicity. Drug combinations offer potentially higher efficacy and lower individual drug dosage. In this paper, we report a new application of fractional factorial designs to investigate a biological system...

An investigator who plans to conduct an experiment with multiple independent variables must decide whether to use a complete or reduced factorial design. This article advocates a resource management perspective on making this decision, in which the investigator seeks a strategic balance between service to scientific objectives and economy. Considerations in making design decisions include wheth...

Determining the optimal dose of coagulant required to perform flocculation is critical in most water treatment plants’ planning and operation. This study implemented a 2k–p fractional factorial design experiments identify factors influencing color decrease wastewater from slaughterhouse. The variables assessed were velocity gradient, residence time, primary dosage, chlorine coagulation adjuvant...