# trafic a Suècia

# funcions

diferenciaMitjanes <- function(dades)
{
  dfSi <- subset(dades, limit == "yes")
  dfNo <- subset(dades, limit == "no")

  mSi <- mean(dfSi$y)
  mNo <- mean(dfNo$y)
  dif <- mSi - mNo
  return(dif)
}

maximNombreAccidents <- function(dades, any)
{

  # suposem que el mamix es unic

  dfAny    <- subset(dades, year == any)
  maxim    <- max(dfAny$y)
  dfDiaMax <- subset(dfAny, y == maxim)
  limit    <- dfDiaMax$limit
  return (c(maxim, limit))
}



# programa principal

# definicio taula de prova

year    <- c(1961, 1961, 1961, 1962, 1962)
day     <- c(1, 2, 3, 4, 5)
limit   <- c("no", "no", "no", "yes", "yes")
y       <- c(9, 11, 9, 15, 9)
Traffic <- data.frame(year, day, limit, y,
                      stringsAsFactors=FALSE)

cat("\nDades de prova: \n")
print(Traffic)
dif <- diferenciaMitjanes(Traffic)
cat("\nDiferencia si-no: ", dif, "\n")

any <- 1961
maxim_limit <- maximNombreAccidents(Traffic, any)
cat("any:   ", any, "\n")
cat("maxim: ", maxim_limit[1], "\n")
cat("limit: ", maxim_limit[2], "\n")

any <- 1962
maxim_limit <- maximNombreAccidents(Traffic, any)
cat("any:   ", any, "\n")
cat("maxim: ", maxim_limit[1], "\n")
cat("limit: ", maxim_limit[2], "\n")

# base de dades

cat("\nBase de dades: ")
library(MASS)
data(Traffic)
#print(Traffic)

dif <- diferenciaMitjanes(Traffic)
cat("\nDiferencia si-no: ", dif, "\n")

any <- 1961
maxim_limit <- maximNombreAccidents(Traffic, any)
cat("any:   ", any, "\n")
cat("maxim: ", maxim_limit[1], "\n")
cat("limit: ", maxim_limit[2], "\n")

any <- 1962
maxim_limit <- maximNombreAccidents(Traffic, any)
cat("any:   ", any, "\n")
cat("maxim: ", maxim_limit[1], "\n")
cat("limit: ", maxim_limit[2], "\n")