10   Question 3 continued (c) Provide an overall summary for a reader with limited statistical knowledge of the main findings from Figure 1 and Figure 2. (3) _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ (Total for Question 3 is 8 marks) Turn over 11   4 A farmer wanted to maximise the spring oat yield, tonnes per hectare, that she could get from a field. The farmer was able to control two factors • variety of oat seed planted: Aspen, Canyon, Delfin or Merlin • concentration of fertiliser used: 10%, 20% or 30% She wanted to investigate whether either of these factors might have an impact on the yield. For her experiment, she split a field into four strips and randomly allocated one of the four different types of oat seeds for planting in each strip. She then subdivided each strip into three smaller plots and randomly allocated one of the three different fertiliser concentrations to each plot during the growing season. At harvest time, she measured the oat yield for each plot. Figure 3 gives the plot yields in tonnes per hectare. Plot fertiliser concentration Oat seed variety 10% 20% 30% Total Aspen 5.5 5.8 5.7 17 Canyon 5.6 5.6 5.5 16.7 Delfin 5.5 5.8 5.6 16.9 Merlin 5.8 6.1 6.3 18.2 Total 22.4 23.3 23.1 68.8 Figure 3 Note that xij 2 ∑ ∑ = 395.14