PrisonStress: Stress in prison

In PairedData: Paired Data Analysis

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

Source

Private communication. Charlotte Verdot, CRIS, Lyon 1 University, FRANCE

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

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)

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


	Two Sample t-test

data:  difference by PrisonStress$Group
t = 3.8616, df = 24, p-value = 0.0007469
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
  5.25916 17.33478
sample estimates:
mean in group Control   mean in group Sport 
             7.363636             -3.933333 

Analysis of Variance Table

Response: PSSafter
                Df Sum Sq Mean Sq F value   Pr(>F)   
PSSbefore        1 228.88 228.878  7.0624 0.014383 * 
Group            1 281.66 281.663  8.6911 0.007436 **
PSSbefore:Group  1  38.83  38.829  1.1981 0.285534   
Residuals       22 712.98  32.408                    
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Error: Subject
          Df Sum Sq Mean Sq F value Pr(>F)
Condition  1   46.8   46.85   0.457  0.506
Residuals 24 2461.9  102.58               

Error: Within
               Df Sum Sq Mean Sq F value   Pr(>F)    
Time            1    9.3     9.3   0.343 0.563710    
Condition:Time  1  405.0   405.0  14.912 0.000747 ***
Residuals      24  651.7    27.2                     
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

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