Questions to be addressed

The specific questions the case study aims to address are:

• Does spent yeast increase weight gain and feed efficiency and, if so, is there a relationship between increased performance and level of spent yeast?
• Does spent yeast reduce mortality and, if so, is there a relationship between decreased mortality and level of spent yeast?

As will be discovered, there are problems in the way that the study has been designed in order to enable the above questions to be addressed satisfactorily. We shall discuss:

• why the design is unsuitable for statistical analysis;
• how we can redesign the experiment to allow statistical analysis to be undertaken;
• how we can take into account particular features of the housing that might allow reduction of residual random variation.