b. Based on the plot alone, comment on the strength of evidence of a difference in the amount of
fertilizer dispensed by the three types of spreaders.Volunteers with no particular training were used because regular homeowners are the population of
interest. However, one researcher points out that there may be very different skill levels among the
volunteers. He suggests using a randomized block design, with each volunteer as a block. Each
volunteer will use all three spreaders in a randomized order. They ran the experiment with just five
volunteers using this design. The results, along with the operator of the spreader, are displayed below.
c. Based on the plot above, comment on the association between the operator of the spreader and the
amount of fertilizer dispensed.To remove the effect of the operators’ skill levels on the response variable, the researchers calculated
the mean amount dispensed for each operator. Miya’s amounts dispensed are given in the table below.