Description
Questions
1. Draw an appropriate faceted graph showing how barley yield varied by year at each location,
using color as necessary. (Note: Lines might be better than dots here.) When looking at
successive years, was it more common for the yields to move in the same direction at all
locations, or was it more common for the yields to increase at some locations and decrease at
others?
2. Fit a model with yield as the response and gen (variety), year, and site as explanatory
variables, with the goal of determining whether Morris 1931-1932 is an anomaly. Justify why
you chose this model and not some other one. Because of outliers, you should use a robust
fitting method.
3. Draw plots of the fit and/or residuals with the goal of determining whether Morris 1931-1932
is a mistake, or whether it can be explained as natural variation. As best as you can tell, was
there a mistake?
