Answer

This research consisted of two independent variables (irrigation and fertilization) therefore you should have conducted a two-way ANOVA. The frequency distribution graph showed that the data are normally distributed, therefore there is no need to use a transformation. The results of the ANOVA indicate that irrigation, fertilization and the relationship between the two have significant (P<0.001) effects on the plant biomass. The null hypothesis should be rejected in favour of the alternate hypothesis. The results of this analysis could be represented in a bar graph: Figure 1. The effect of fertilisation and irrigation on plant biomass. Error bars represent standard error.