Level: Intermediate
Job Function: Analyst / Scientist / Engineer
Jacqueline Asscher, Senior Lecturer, Kinneret College on the Sea of Galilee
When experiments have a split plot structure, this should be considered in both design and analysis. A common example is an experiment conducted to improve a process that runs in batches, where some factors are changed between batches and other factors are changed within batches, resulting in runs that are not fully independent. The split plot structure may be inherent in the process being investigated or in the experimental setup, or may be adopted by choice either to save time or money or to improve the design. In the case study, some factors are related to material preparation, and other factors are related to the processing of the material into the final product. In the training session for practitioners, the JMP tools for designing, evaluating and comparing experiments are used to explore alternative strategies for choosing a design. The candidate designs considered include the default and user-specified designs built by JMP and designs built from scratch by the user. For example, it is usually cheaper to include minimal whole plot replication, and we explore the consequences of adopting this strategy. The pedagogical aim is to simultaneously teach the topic and the use of the JMP tools.