if(!requireNamespace('lattice', quietly = TRUE)){
   install.packages('lattice', dependencies=TRUE, repos='http://cran.rstudio.com/')
}
library(lattice)

source('../../Data/get_football_data.R')
DF = get_football_data()

min_distance = min(c(DF$Air, DF$Helium))
max_distance = max(c(DF$Air, DF$Helium))

plot(DF$Trial, DF$Air, type='l', col='black', ylim=c(min_distance, max_distance), xlab='Trial', ylab='Distance')
lines(DF$Trial, DF$Helium, type='l', col='green')
grid()

library(reshape2)

DF_melt = melt(DF, id.vars='Trial', measure.vars=c('Air', 'Helium'), variable.name='Filling', value.name='Distance')

## Plot the histogram:
##
histogram(~ Distance | Filling, layout=c(1, 2), data=DF_melt, n=10)

## Perform a t-test:
##
x=DF$Air
y=DF$Helium
res = t.test(x, y)
print(res)