6.31. Peanuts are an important crop in parts of the southern United States. In an effort to develop
improved plants, crop scientists routinely compare varieties with respect to several
variables.The data for one two-factor experiment are given in Table 6.17 on page 354.
Three varieties (5, 6, and 8) were grown at two geographical locations (1, 2) and, in this
case, the three variables representing yield and the two important grade-grain characteristics
were measured.The three variables are
X1=Yield (plot weight)
X2=Sound mature kernels (weight in grams—maximum of 250 grams)
X3=Seed size (weight, in grams, of 100 seeds)
There were two replications of the experiment.
(a) Perform a two-factor MANOVA using the data in Table 6.17. Test for a location
effect, a variety effect, and a location-variety interaction. Use =.05
(b) Analyze the residuals from Part a. Do the usual MANOVA assumptions appear to
be satisfied? Discuss.
(c) Using the results in Part a, can we conclude that the location and>or variety effects
are additive? If not, does the interaction effect show up for some variables, but not
for others? Check by running three separate univariate two-factor ANOVA
This solution is comprised of a detailed explanation on main effect in two factor or two way MANOVA. Full description is given for the table with respect to two factors along with all description of cells (rows and columns). The analysis was performed with SPSS. The SPSS output and data set is also attached with the solution.