R: Barley data from Preece (1982, Table 1)

Barley

R Documentation

Barley data from Preece (1982, Table 1)

Description

This dataset presents 12 paired data corresponding to the yields of Glabron and Velvet Barley, grown on different farms. The values from farm 12 are quite different.

Usage

data(Barley)

Format

A dataframe with 17 rows and 3 columns:

[,1]	Farm	factor
[,2]	Glabron	numeric	yields (bushels per acre)
[,3]	Velvet	numeric	yields

Source

Leonard, W.H. & Clark, A.G. (1939) Field Plot Techniques. Burgess: Minneapolis.

References

Preece D.A. (1982) t is for trouble (and textbooks): a critique of some examples of the paired-samples t-test. The Statistician, 31 (2), 169-195.

Examples

data(Barley)

# Visualizing a clear outlier
with(Barley,plot(paired(Glabron,Velvet),type="BA"))

# Results form the paired t test and paired Yuen test are similar
with(Barley,t.test(paired(Glabron,Velvet)))
with(Barley,yuen.t.test(paired(Glabron,Velvet)))

# Nevertheless the outlier inflates the location (numerator) and
# scale (denominator) standard statictics for the difference
with(Barley,summary(paired(Glabron,Velvet)))