Comparison of the stellar parameters derived using the three methods discussed in Sects. 4.3.1 till 4.3.3 with the reference values (Table 2). On each y-axis is indicated the difference between the values we have obtained and the reference value (indicated by a subscript “r”). Method 1 is indicated by red symbols, Method 2 by black, and Method 3 is indicated by cyan symbols. Different symbols represent the different stars (as indicated in the figure, note that each symbol represent two stars. They should be easy to identify thanks to their different T_eff). Note that some stars have more than one spectrum analysed (see Sect. 2.1.1). The stars can be identified by their recommended T_eff which is plotted on the x-axis. The dashed line indicates the separation of “cool” (left) and “warm” (right) giants (see Sect. 4.3.2).