2.3.3. Statistical analyses Statist

2.3.3. Statistical analyses
Statistical tests were performed to test differences between the knowledge of different age groups and locations. The data of village age, gender, informant age, and numbers of plants known by the informants were analyzed using Principal Component Analysis (PCA) using Q-mode PCA. The data of informant age and numbers of medicinal plants known by the informant were also analyzed using a linear regression in R Programming Language version 2.15.3 (R Core Team 2013). The calculation was done by a singular value decomposition of data matrix (R Core Team 2013). Furthermore, the numbers of medicinal plants known by the informants and the continuous variable of informant age were analyzed using a linear regression. The knowledge of medicinal plants between females and males were compared using Chi-square statistics, t-test and analysis of variance (Teklehaymanot, 2009).