2. Researchers were interested in which of four common onigiri types (tuna and mayo, salmon flakes, pickled plum, and co

[answerhappygod]

2. Researchers were interested in which of four common onigiri
types (tuna and mayo, salmon flakes, pickled plum, and cod roe) is
best tasting, so they recruited 7 tasters and used a randomized
complete block design to investigate. Each taster tried all four
onigiris in a random order, and gave a taste value for each type.
The data are available here. Please use R.
a) Show a boxplot of the taste ratings by onigiri type.
Does the set of boxplots suggest that a difference in mean taste
may exist?
b) Write a model for the taste ratings appropriate for a
randomized complete block design. Conduct an RCB ANOVA to test for
a difference in mean ratings by type. State the null and
alternative hypotheses, give the F value and its df, report the P
value and make your conclusion.
c) Show the residual by predicted plot and the normal plot for
the residuals. Comment on each plot and what you conclude from each
plot about the model assumptions.
d) Show an 'interaction plot' of tasters and ratings to
graphically assess the RCB additivity assumption. Give your
assessment of whether the additivity assumption seems
reasonable.
e) Calculate the relative efficiency for this RCB design.
Interpret the value, does it appear that the blocking was
useful?