Results from an Experiment on Plant Growth

Description

Results from an experiment to compare yields (as measured by dried weight of plants) obtained under a control and two different treatment conditions.

Usage

PlantGrowth

Format

A data frame of 30 cases on 2 variables.

The levels of group are ‘ctrl’, ‘trt1’, and ‘trt2’.

Source

Dobson, A. J. (1983) An Introduction to Statistical Modelling. London: Chapman and Hall.

Examples

## One factor ANOVA example from Dobson's book, cf. Table 7.4:
require(stats); require(graphics)
boxplot(weight ~ group, data = PlantGrowth, main = "PlantGrowth data",
        ylab = "Dried weight of plants", col = "lightgray",
        notch = TRUE, varwidth = TRUE)
anova(lm(weight ~ group, data = PlantGrowth))

Results

R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(datasets)
> png(filename="/home/ddbj/snapshot/RGM3/R_rel/result/datasets/PlantGrowth.Rd_%03d_medium.png", width=480, height=480)
> ### Name: PlantGrowth
> ### Title: Results from an Experiment on Plant Growth
> ### Aliases: PlantGrowth
> ### Keywords: datasets
> 
> ### ** Examples
> 
> ## One factor ANOVA example from Dobson's book, cf. Table 7.4:
> require(stats); require(graphics)
> boxplot(weight ~ group, data = PlantGrowth, main = "PlantGrowth data",
+         ylab = "Dried weight of plants", col = "lightgray",
+         notch = TRUE, varwidth = TRUE)
Warning message:
In bxp(list(stats = c(4.17, 4.53, 5.155, 5.33, 6.11, 3.59, 4.17,  :
  some notches went outside hinges ('box'): maybe set notch=FALSE
> anova(lm(weight ~ group, data = PlantGrowth))
Analysis of Variance Table

Response: weight
          Df  Sum Sq Mean Sq F value  Pr(>F)  
group      2  3.7663  1.8832  4.8461 0.01591 *
Residuals 27 10.4921  0.3886                  
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>