barley                package:lattice                R Documentation

Yield data from a Minnesota barley trial

Description:

     Total yield in bushels per acre for 10 varieties at 6 sites in
     each of two years.

Usage:

     barley

Format:

     A data frame with 120 observations on the following 4 variables.

     yield Yield (averaged across three blocks) in bushels/acre.

     variety Factor with levels '"Svansota"', '"No. 462"',
          '"Manchuria"', '"No. 475"', '"Velvet"', '"Peatland"',
          '"Glabron"', '"No. 457"', '"Wisconsin No. 38"', '"Trebi"'.

     year Factor with levels '1932', '1931'

     site Factor with 6 levels:  '"Grand Rapids"', '"Duluth"',
          '"University Farm"', '"Morris"', '"Crookston"', '"Waseca"'

Details:

     These data are yields in bushels per acre, of 10 varieties of
     barley grown in 1/40 acre plots at University Farm, St. Paul, and
     at the five branch experiment stations located at Waseca, Morris,
     Crookston, Grand Rapids, and Duluth (all in Minnesota).  The
     varieties were grown in three randomized blocks at each of the six
      stations during 1931 and 1932, different land being used each
     year of the test.

     Immer et al. (1934) present the data for each
     Year*Site*Variety*Block. The data here is the average yield across
     the three blocks.

     Immer et al. (1934) refer (once) to the experiment as being
     conducted in 1930 and 1931, then later refer to it (repeatedly) as
     being conducted in 1931 and 1932.  Later authors have continued
     the confusion.

     Cleveland (1993) suggests that the data for the Morris site may
     have had the years switched.

Author(s):

     Documentation contributed by Kevin Wright.

Source:

     Immer, R. F., H. K. Hayes, and LeRoy Powers. (1934).  Statistical
     Determination of Barley Varietal Adaptation.  _Journal of the
     American Society of Agronomy_, *26*, 403-419.

References:

     Cleveland, William S. (1993). _Visualizing Data_.  Hobart Press,
     Summit, New Jersey.

     Fisher, R. A. (1971). _The Design of Experiments_.  Hafner, New
     York, 9th edition.

See Also:

     'immer' in the MASS package for data from the same experiment 
     (expressed as total yield for 3 blocks) for a subset of varieties.

Examples:

     # Graphic suggesting the Morris data switched the years 1931 and 1932
     # Figure 1.1 from Cleveland
     dotplot(variety ~ yield | site, data = barley, groups = year,
             key = simpleKey(levels(barley$year), space = "right"),
             xlab = "Barley Yield (bushels/acre) ",
             aspect=0.5, layout = c(1,6), ylab=NULL)

