PairedData (version 1.1.1)

PrisonStress: Stress in prison

Description

This dataset gives the PSS (stress measurement) for 26 people in prison at the entry and at the exit. Part of these people were physically trained during their imprisonment.

Usage

data(PrisonStress)

Format

A dataframe with 26 rows and 4 columns.

[,1]	Subject	factor	anonymous subjects
[,2]	Group	factor	sport or control
[,3]	PSSbefore	numeric	stress measurement before training
[,4]	PSSafter	numeric	stress measurement after training

References

Verdot, C., Champely, S., Massarelli, R. and Clement, M. (2008) Physical activities in prison as a tool to ameliorate detainees mood and well-being. International Review on Sport and Violence, 2.

Examples

# NOT RUN {
data(PrisonStress)

# The two groups are not randomized! 
# The control group is less stressed before the experiment
with(PrisonStress,boxplot(PSSbefore~Group,ylab="Stress at the eginning of the study"))

# But more stressed at the end!
with(PrisonStress,boxplot(PSSafter~Group,ylab="22 weeks later"))

# So the effects of physical training seems promising
with(PrisonStress,plot(paired(PSSbefore,PSSafter),groups=Group,type="BA",facet=FALSE))

# Testing using gain scores analysis
difference<-PrisonStress$PSSafter-PrisonStress$PSSbefore
t.test(difference~PrisonStress$Group,var.equal=TRUE)

# Testing using ANCOVA
lmJail<-lm(PSSafter~PSSbefore*Group,data=PrisonStress)
anova(lmJail)

# Testing using repeated measures ANOVA
PSS<-c(PrisonStress$PSSbefore,PrisonStress$PSSafter)
Time<-factor(rep(c("Before","After"),c(26,26)))
Subject<-rep(PrisonStress$Subject,2)
Condition<-rep(PrisonStress$Group,2)
aovJail<-aov(PSS~Condition*Time+Error(Subject))
summary(aovJail)
# }