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Standard errors of differences of means3.7 Practical 51Table Fumigant Fumigant Fumigant FumigantAmount Type AmountTyperep. unequal 16 unequal unequald.f. 35 35 35 35s.e.d. 0.1596 0.2226 min.rep0.0949 0.1097 0.1382 0.1760 max-min0.1129X 0.1113X max.rep(No comparisons in categories where s.e.d. marked with an X)You can find more information about analysis of covariance in GenStat in the Guide tothe GenStat Command Language, Part 2, Section 4.3.3.7 PracticalSpreadsheet file Ratmuscles.gshcontains data from an experiment tostudy the effect of electricalstimulation in preventing thewasting away of denervatedmuscles, using rats as the subjects(Solandt, DeLury & Hunter, 1943,Archives of Neurology &Psychiatry, 49, 802-807; also seeC o c h r a n & C o x , 1 9 5 7 ,Experimental Designs 2nd Edition,page 176). There were threetreatment factors: length of eachtreatment, number of treatmentperiods per day and the type ofcurrent. The experiment used acomplete randomized block designwith two blocks. The denervated Figure 3.15muscles were the gastrocnemiusmuscles on one side of the rat. To improve precision, the normal muscle on the other sideof each rat was also measured, for use as a covariate in the analysis.Analyse the experiment. Has the covariate improved the precision of the estimates?Which tables of means would you present in the report?