Exploration & description

The arcsine transformation is often recommended for percentage or proportional data. Here it is unnecessary since the primary interest in the analysis is to compare mean percentage germination across sucrose concentrations. Although the distribution across individual fields of view will tend to be binomial, the mean values for each slide will approximate more closely to normality.

Two box plots were then produced for percentage germination grouped by sucrose concentration using each of CS9Data1a and CS9Data1b in turn. The two box plots naturally show the same trend in mean values but illustrate the respective variations in percentage germination at the field of view and slide levels, respectively. The 'whisker' lines are much longer in the first box compared with the second indicating the large variations among different fields of view compared with the variations in their means.