Corn: Corn data (Darwin)

In PairedData: Paired Data Analysis

Description

This dataset presents 15 paired data corresponding to the final height of corn data (Zea Mays), one produced by cross-fertilization and the other by self-fertilization. These data were used by Fisher (1936) and were published in Andrews and Herzberg (1985).

Usage

data(Corn)

Format

A dataframe with 15 rows and 4 columns:

[,1]	pair	numeric
[,2]	pot	numeric
[,3]	Crossed	numeric	plant height (inches)
[,4]	Self	numeric	plant height

Source

Darwin, C. (1876). The Effect of Cross- and Self-fertilization in the Vegetable Kingdom, 2nd Ed. London: John Murray.

References

• Andrews, D. and Herzberg, A. (1985) Data: a collection of problems from many fields for the student and research worker. New York: Springer.

• Fisher, R.A. (1936) The design of Experiments. Oliver & Boyd: London

Examples

data(Corn)

# Visualizing two outliers
with(Corn,slidingchart(paired(Crossed,Self)))

# Very bad matching in these data
with(Corn,cor.test(Crossed,Self))
with(Corn,winsor.cor.test(Crossed,Self))


# So the two-sample test is slightly 
# more interesting than the paired test
with(Corn,t.test(Crossed,Self,var.equal=TRUE))
with(Corn,t.test(Crossed,Self,paired=TRUE))

# The Pitman-Morgan test is influenced by the two outliers
with(Corn,Var.test(paired(Crossed,Self)))
with(Corn,grambsch.Var.test(paired(Crossed,Self)))
with(Corn,bonettseier.Var.test(paired(Crossed,Self)))

# Lastly, is there a pot effect?
with(Corn,plot(paired(Crossed,Self)))
with(Corn,plot(paired(Crossed,Self),group=pot))

Example output

Loading required package: MASS
Loading required package: gld
Loading required package: mvtnorm
Loading required package: lattice
Loading required package: ggplot2

Attaching package: 'PairedData'

The following object is masked from 'package:base':

    summary


	Pearson's product-moment correlation

data:  Crossed and Self
t = -1.416, df = 13, p-value = 0.1803
alternative hypothesis: true correlation is not equal to 0
95 percent confidence interval:
 -0.7393644  0.1805101
sample estimates:
       cor 
-0.3655551 


	winsorized correlation, trim=0.2

data:  Crossed and Self
t = -0.83856, df = 7, p-value = 0.4294
alternative hypothesis: true (winsorized) correlation is not equal to 0
sample estimates:
       cor 
-0.2265288 


	Two Sample t-test

data:  Crossed and Self
t = 2.4986, df = 28, p-value = 0.01861
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
  3.879567 39.187100
sample estimates:
mean of x mean of y 
 161.5333  140.0000 


	Paired t-test

data:  Crossed and Self
t = 2.1781, df = 14, p-value = 0.04699
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
  0.3290402 42.7376265
sample estimates:
mean of the differences 
               21.53333 


	Paired Pitman-Morgan test

data:  Crossed and Self
t = 2.2544, df = 13, p-value = 0.04206
alternative hypothesis: true ratio of variances is not equal to 1
95 percent confidence interval:
 1.043095 8.767832
sample estimates:
variance of x variance of y 
     837.2667      276.8571 


	Paired Grambsch test

data:  Crossed and Self
z = 1.3648, p-value = 0.1723
alternative hypothesis: true ratio of variances is not equal to 1


	Paired Bonett-Seier test

data:  Crossed and Self
z = 0.81689, p-value = 0.414
alternative hypothesis: true ratio of means absolute deviations is not equal to 1
95 percent confidence interval:
 0.5994786 3.4661646
sample estimates:
 mean abs. dev. of x  mean abs. dev. of y 
            18.06667             12.53333 

PairedData documentation built on May 1, 2019, 6:49 p.m.