Penanganan Data Pengamatan Berulang dengan Analisis Ragam (ANOVA) dan Analisis Ragam Peubah Ganda (MANOVA)

Abstract

Epipyropidae is an ectoparasitic moth that attacks cashew planthopper and can used as biological control agent. This ectoparasitoid attacks it host by sucking its body fluids. The cashew planthopper’s attack and parasitization levels are responses which are measured repeatedly at different times on the same experimental unit. Repeated observations experiment requires an analytical model to see the effect of the treatment and growth response during the observation period, so the effect of time can be studied. The appropriate design for this experiment is a completely randomized design (CRD) in time. Time as an additional factor in CRD in time is viewed as a two-factor design with split-plot design. In this experiment, the location becomes the main plot and time becomes the subplot. This experiment use Univariate Analysis of Variance (ANOVA) and Multivariate Analysis of Variance (MANOVA) on the subplot component. The assumption test of homogeneity of covariance matrix shows a significant result but sphericity assumption is violated. Violation of this assumption causes the degrees of freedom in the ANOVA subplot components should be corrected with Huynh-Feldt epsilon and tested with MANOVA. Results of ANOVA with adjusted degrees of freedom and MANOVA show significant values for time and interaction for two response variables. Significant result for interaction indicates that there are differences in the average of each response variable at each location from time to time in the observation period.