A researcher would like to test the effectiveness of four different treatments in controlling two-spotted spider mites (TSM) in commercial greenhouses. Four greenhouses were used for the study. Within each greenhouse, eight potted plants were inoculated with TSM. One of the four treatments was applied to all the pots in each of the four greenhouses. At the end of the treatment period, the number of TSM was counted on each of the potted plants in each of the greenhouses.

The unit of analysis for this study is greenhouse. This study is unreplicated. Plugging the maximum reasonable value of the intraclass correlation coefficient (ICC) into analysis equations, an appropriate analysis of this study is conducted. This method maintains the Type-1 error rate. This study demonstrates the use of the Rho Information Analysis (RIA) in analyzing unreplicated experiments.

Key words: Intraclass correlation coefficient, unreplicated experiment, RIA analysis